Roman Military Forces – Imperial Period I

The legion of the Imperial period, which had developed from the legion of the Marian reforms was, tactically and administratively, a self-contained military organization. Internally, the legion was divided in many ways. Duty rosters and administrative procedures were subject to strict regulations, as well as the complicated principles of promotion within a sometimes inscrutable hierarchy (v. Domaszewski 1967). After the military reforms of Marius around 100 BC, professional soldiers who already had Roman citizenship upon entry into the force served in the legion. From then onwards, the tactical basis was the cohort, a subunit of about 500 men, which was further divided into six centuries of 80 combat troops. Each legion consisted of ten cohorts, around 5500–6400 men, with (probably only from the Flavian period) the first cohort, as the leading subunit about twice the size of the others, with c.800 men. But the actual strength of a legion would rarely have matched the nominal strength. Following H. von Petrikovits (1975), the latter can be simplified as follows (* = pure estimates).


One should not assume that all soldiers of a legion always stayed in camp in peacetime, for several hundred soldiers were assigned to special duties and were often based far outside their garrison sites.

Among the soldiers of a legion, there were some 5,000 men serving as combat troops. Most were employed as ‘common’ infantrymen, as milites gregarii. They were enrolled in the legion between 17 and 20 years of age, most having previously learned a craft. They now had every chance to advance in the complicated promotion system of the Roman army. The normal period of service for legionary soldiers was 20 years; an honourably discharged veteran then remained with his unit for a further five years (veteranus sub vexillo). After 25 years of service, he was able to return to civilian life with a pension (praemia militiae), which consisted of cash and/or a land grant. At least in theory: in the early Imperial period there were repeated problems of mutiny, because soldiers were not released on time, but were forced to serve for longer. But it was also possible to continue to serve as a volunteer (voluntarius). The veteran with regular service proudly stressed that he was a missus honesta missione, ‘dismissed with an honourable discharge’. There were also premature retirements as a result of disease (missio causaria) or even dishonourable dismissal from the army (missio ignominiosa).

The common soldiers performed their daily duties within one of the ten cohorts. With the exception of the first, each cohort in turn consisted of six centuries (‘hundreds’) each commanded by a centurion. Eighty common soldiers served in every century; the remaining 20 were composed of specialists such as craftsmen, doctors, soldiers with administrative tasks, legionary riders, and so on. Two centuries formed a maniple in the 2nd and 3rd centuries, by then only important administratively and for the cohesion of the soldiers. Thus, each cohort had three maniples, the legion 30 of them; as the types of armament were named in the same way as in the early days of the Republic – triarii, principes and hastati – the maniples carried the same names. Each maniple had its own standard (signum).

Each legion possessed 120 horsemen (equites legionis). They probably served primarily as dispatch riders and messengers. In battle, they fought together with the legion’s auxiliary cavalry, separate from the legion itself.

Legionary commanders and military tribunes

The commander of a legion, the legatus Augusti pro praetore legionis, was appointed by the emperor. If only one legion was based in a province, he always also fulfilled the office of governor. He thus administered both the military and the civil administration of a province. The next highest-ranking officer after the legionary legate was a senatorial military tribune, the tribunus militum laticlavius. Since this officer, by birth or by the favour of the emperor, was a contender for the post of quaestor (minimum age requirement 25 years) and thus of senatorial rank, he was allowed to wear a broad purple border (latus clavus) on his tunic. He was very young, usually only 18 to 20 years old. Nevertheless, he was the highest ranking officer after the legionary commander. Lacking a fixed command role, he was a deputy in the event of war. Such a senatorial military tribune often had a brilliant career in the military and the administration before him.

From the second tier of Roman nobility came the equestrian military tribunes who, because of the narrow purple stripe on their tunics, were called tribuni militum angusticlavii. There were five of them in a legion. They too were often at the beginning of great careers in the procuratorial service, for which service as an equestrian officer was a precursor. These equestrian tribunes spent most of their time in administrative tasks. Sometimes they also led a cohort, commanded some special detachments, or helped the commander in other important tasks.

Legionary prefects

The military tribunes were serving in the army for only a relatively short term, quickly continuing their career path of mixed military and civilian postings. Accordingly, they cannot really be called professional soldiers. Their practical military experience was probably not very wide-ranging in most cases. However, there was at least one officer in the command structure of each legion who had worked his way up from recruit as a professional soldier in the army: the praefectus castrorum (legionis). In terms of rank, he was below the senatorial tribune, but above the equestrian tribunes. He belonged to the equestrian order. The area of responsibility of legionary prefects could be described as base commander and logistics officer. He was responsible for the camp and the associated legionary territory, also controlling the entire roster including guard duties. In the period from around the Emperor Domitian (AD 81–96) to Emperor Septimius Severus (AD 193–211), they were called praefectus castrorum with the occasional addition of legionis, but afterwards just praefectus legionis. This title they retained even when, after Gallienus (AD 253–68), they commanded the entire legion, because there were now no longer any senatorial officers in the legion, although they had already done so earlier in the absence of the legatus legionis and tribunus militum laticlavius. All the above-mentioned officers had their own administrations.


Centurions can be described as the military backbone of a legion. These officers – equivalent to the modern rank of captain – were professional soldiers through and through. They usually commanded the centuries, administratively and tactically the smallest subunits of a legion. Ultimately, they were responsible for ensuring that, in the event of war, military operations were performed successfully. Therefore, they had to pay particular attention to the maintenance of discipline in troops in time of peace. As part of this duty they enforced the commands of the legion’s high command with the ordinary soldiers. They also monitored the daily routine of the combat troops, drill as well as manoeuvres, preparation of parades, and inspections, and likewise the introduction of new recruits or the cleaning of accommodation. In battle, they were at the forefront. In more peaceful times, centurions also commanded work details of legionaries in mines, quarries, or brick kilns, generally on imperial and state possessions. Sometimes they were temporarily employed as commanders of building detachments, such as for the erection of forts or fort baths for auxiliary units.

As a sign of his disciplinary authority, the centurion carried a vine staff and wore greaves, a transverse crest, and a gold ring although, after Septimius Severus, non-commissioned officers (principales) also had these.

Most centurions had been promoted from the lower ranks and only achieved their position after 13 to 20 years of service. The evocati, veterans who voluntarily returned to the colours, also had good career opportunities, most of them being promoted directly to centurions.

According to the number of centuries, there were 60 centurions in a legion. They were allotted to the cohorts and again to the maniples. Since each of the three maniples in a cohort comprised two centuries, each had two centurions. Like military tribunes, these were divided between a prior (more experienced) and a posterior (less experienced). In pithy military language, therefore, the six centurions in each cohort were named according to the old manipular terms pilus prior and pilus posterior, princeps prior and princeps posterior, and hastatus prior and hastatus posterior. The commander of the entire cohort was the pilus prior. The cohorts in turn were numbered from the first (prima) to the tenth (decima), so that each centurion could be precisely identified. Of course, the difference in rank between the centurions of the second to the tenth cohort was not particularly serious. Only the centurions of the first cohort (primi ordines) occupied a special position.

This was because the entire first cohort significantly differed from the other nine in many ways. It was almost twice as strong, although it had only six centuries; but it had another 400 soldiers: mainly the ordinary soldiers and NCOs under the legionary prefect, as well as soldiers on long-term duty outside the garrison base. The most senior centurion, the primus pilus, also led two centuries (Dobson 1978). This position, apparently only held for one year, could even lead to elevation to equestrian rank. The primus pilus was first and foremost the centurions’ spokesman with the commander.

After his year in office, this officer (with a minimum age of 50 years) either retired and played a prominent role in his home region or was next promoted to praefectus castrorum legionis. With that, his military career was finally over. However, if – after the primipilate – he went to the capital city of Rome and served as a tribune in the fire service (cohortes vigilum), city cohorts (cohortes urbanae) or in the imperial bodyguard (cohortes praetoriae) as tribune, he could return to the legion as primipilus iterum (‘primus pilus returning for a second time’); then he occupied a special place on the staff of the legion commander and ranked immediately below the senatorial military tribune. Such men had a good chance of being entrusted with a post as an equestrian in command of a legion in Egypt or even with an imperial procuratorship, i.e. a high and well-paid administrative office. The majority of the men certainly never got so far and were discharged as centurions. However, during his active career, a centurion did not have to remain with the same legion. The reasons for transfers differed; they might be found on a personal level or could be a result of patronage. Technical specialists also often changed postings.

Principales and immunes

One group of soldiers, entrusted with special tasks, ranked above ordinary soldiers but below centurions. They were called immunes (exempt from fatigues, corresponding roughly to modern privates) and principales on a slightly higher level (ranking similar to modern NCOs). Since the two terms (the latter first appeared at the beginning of the 2nd century) were not always used unambiguously, it is often not possible to specify the exact rank of individual posts (it is even more difficult to determine possible career structures). In addition, it is to be expected that one or other was subjected to fluctuations in status over time, i.e. it would increase or decrease in status. These included the weapons orderlies (armorum custodes) assigned to each century. Although they were still among the immunes around AD 180, a few decades later they were definitely principales. The same was probably true for scribes and copyists, the librarii and exacti, who, if they worked in the office of the governor, belonged to the sesquiplicarii, especially in the 3rd century AD. The main difference between the immunes and the principales lay in their pay and that the principales were exempt from the duties of ordinary soldiers by virtue of rank, while it was granted to the immunes specifically to exercise their special duties. In turn, principales were further graded according to whether they received one-and-a-half times or twice the basic pay: whether one was a sesquiplicarius or dupl(ic)arius.

Whoever had achieved this ‘non-commissioned officer rank’, enjoyed further, additional privileges, such as more spacious accommodation and communal areas in camp. Nevertheless, there were differences even within this rank. For daily routine, it was important whether a principalis belonged to the combat troops, and thus served in a century (such as, for example, the optio, tubicen, and signifer) or on the staff. Among staff positions, another two groups are distinguishable: office posts (officiales), designated according to the rank of their officers, and tactical posts which – seconded from the centuries – served on the staff of the governor, like the eagle-bearer (aquilifer). He carried the standard of the whole legion, topped with a golden eagle. Apparently always a member of the first cohort, he was the highest-ranking NCO not in an office. This post was not always achieved after a long period of service. It seems that sometimes eagle-bearers (there were possibly two per legion) had previously been standard-bearers (signiferi) and were later even promoted to centurio.

The head of the administrative staff was called the cornicularius, both in military offices as well as in the civil administration of the relevant officium of the governor. He oversaw the lower-ranking clerical staff (e.g. the exacti and librarii), and even undertook clerical work himself, especially in the offices of the lower staff officers. If he worked for the legionary commander and governor, he could hope for promotion to centurion. The beneficiarii consularis reported directly to the governor. They were used for special tasks, for instance the financial and economic control along roads (Schallmayer 1990 and 1992). The signifer carried the signum, a standard with discs attached (Alexandrescu 2010). Apparently, two such standard-bearers belonged to each maniple. In addition, this rank was responsible for monitoring the cohort funds and the savings of the soldiers; he was also responsible for the burial fund. Until the 1st century AD, the frumentarii provided their units with grain; accordingly, they derived their name from it (frumentum = grain). Later, however, they were used for various tasks: as messengers and as a supervisory officers.

The optio commanded the century if the centurion was ill or otherwise incapacitated, also helping him with management tasks. As a kind of ‘sergeant’, he was waiting to join the centurionate. Each maniple had a tubicen, a tuba player (or other brass musician), as well as a cornicen (horn player) (Alexandrescu 2010).

Roman soldiers were given regular pay, which was differentiated according to the rank and service grade of the troops, in return for their by no means easy duties. However, there were deductions from pay for weapons and equipment. In addition, a part of the pay was withheld, to be paid out as a bonus upon honourable discharge from the army – here, something approximating one of the principles of modern national insurance was anticipated. A share of booty during war and one-off donatives upon the accession of a new emperor could on occasion supplement pay.

The total number of legions during the Imperial period repeatedly fluctuated due to losses and new formations, but there were never more than 28 units at the same time.

Roman Military Forces – Imperial Period II

Warrior auxiliary cohort of Batavia , the second half of the 1st century AD.

Batavian auxiliary cavalry – Pablo Outeiral

Auxiliaries (auxilia)

About the same strength as the legions, there was a second part of the Roman army, the so-called auxilia or auxiliary troops (Kraft 1951; Spaul 1994 and 2000). In terms of strength, pay, and legal status, these were ‘second-rate’ units. From the mid-1st century BC, auxiliary troops were mainly used for frontier protection, but when in combat, they operated alongside legionary troops. In the Imperial period, auxiliaries provided all of the cavalry (the few mounted legionaries were insignificant in impact). Those free imperial residents from the provinces who did not initially possess Roman citizenship, the so-called peregrini (= strangers) could enrol in the auxilia. If they had completed 25 years of service and if they had done nothing wrong, then they could get the coveted Roman citizenship.

In the Republic, auxiliary troops were tightly bound to the legions in organization, garrison, and use. They were also housed with them – albeit spatially separated – in the same camps. After the Augustan period, their position changed: they became increasingly independent units and had, from the Claudian period onwards, their own camps – the auxiliary forts.


The auxilia were divided between cavalry and infantry units into alae and cohortes, 500 (quingenaria) or 1,000 (milliaria) men strong. Frequently, there were also mixed units, so-called cohortes equitatae.

A cohors quingenaria peditata consisted of six centuries, each of 80 infantrymen under the command of a centurion; including the staff, it was about 500 men strong. Their commander, the praefectus or praepositus cohortis, usually came from the equestrian order.

A cohors milliaria peditata consisted of ten centuries, each of 80 infantrymen under the command of a centurion; with staff, it was perhaps about 1,000 men strong. Their commander, the tribunus cohortis, usually came from the equestrian order.

The cohors quingenaria equitata was a mixture of infantry and cavalry. It consisted of six centuries of 80 men under the command of a centurion. To these were added six turmae of cavalry; it was probably about 500 men strong. Their commander, the praefectus cohortis, came from the equestrian order.

A cohors milliaria equitata was also a mixed unit of infantry and cavalry. It consisted of ten centuries of 80 men commanded by a centurion. In addition, there were ten turmae of 24 cavalrymen, so together with staff the unit was over 1,000 men strong. Their commander, the tribunus cohortis, came from the equestrian order.

An ala quingenaria consisted of 480 horsemen, who were divided into 16 turmae of 30, the leader of the turma being the decurio (not to be confused with that post on a city council). The ala milliaria consisted of 1,008 horsemen, who were divided into 24 turmae of 42 men. The commander of an ala quingenaria, like the ala milliaria, was always a praefectus alae, drawn from the equestrian order.

Commanders of auxiliary cohorts were appointed by the governor of the province in which they were stationed. In contrast, the commanders of alae, the praefecti alae, were always appointed directly by the emperor in Rome. They completed their military service after the time of Emperor Claudius (AD 41–54) in three tiers, namely in the career of the tres militiae which corresponded to three grades:

1.Prefect of a cohors quingenaria;

2.Military tribune in a legion (tribunus militum legionis angusticlavius ) or as a tribunus cohortis milliariae;

3.praefectus alae quingenariae.

Then, around the middle of the 2nd century AD, a fourth tier was added for the command of an ala milliaria with the militia quarta, only rarely achieved, in the quarta militia equestris, namely the rank of praefectus ala milliariae. This was the highest military rank that an equestrian could attain, very often paving the way for a procuratorship, managing the financial administration of a province.


While the Romans initially drafted auxiliary troops from the able-bodied young men of newly conquered territories and based them away from the recruitment area, over time the majority of units increasingly came from the hinterland of their base, with only a few exceptions. Often, auxiliary units were named after the tribe from which they had been originally recruited, for example the cohors Raetorum. However, if such a Raetian cohort was posted in Britain for a long time, for example, the name became merely traditional, because over time the unit came to be formed mainly from provincials, in other words from Britons. In contrast, there were special forces with indigenous weapons or special abilities that were extremely important to the Roman army. These included, for example, the Batavians from the Lower Rhine. They were not only first-class fighters on foot and on horseback, but they could also do what others apparently could not, crossing water in full armour with their horses. They evidently trained in these skills from early youth. So, along with oriental archers (mainly from Syria), they belonged to those auxiliaries who were not just placed in an area and then raised recruits from around their garrison town, but also kept recruiting from their original recruitment region. Moreover, the officers of these units were aristocrats from the same tribes. There were some auxiliary units (cohortes civium Romanorum) in which Roman citizens served too, while cohortes classicae were a relic of the Civil War, as they were infantry units formed after 27 BC from marines left over after the battle of Actium.

Auxiliary units were also named after the emperor, or an officer under whom they were founded, for example the ala Flavia or ala Indiana (after the Treveran noble Julius Indus). There were also numerous honorary names if the whole unit had performed well, for example pia fidelis (reliable, loyal) or victrix (victorious). Special armament was also occasionally added to the title of the unit, e.g. sagittariorum (archers) or scutata, meaning the troops fought like a legion, with the scutum, the rectangular shield.

Up to the mid-1st century, the auxilia were still closely tied to the legions, tactically as well as spatially and in their accommodation. Only with the formation of stable frontiers on the limites and ripae did the auxilia win more independence and were posted further away from the legions to man the frontiers. (However, an interesting exception is the legionary fortress at Bonn where an additional ala and a cohort were based alongside legio I Minervia until the 3rd century AD.)


With his honourable discharge (honesta missio) after 25 or more years of service, better times began for the auxiliary soldier. The savings that had been withheld for him in the unit coffers and that had built up over the years were paid out to him in cash; in addition he now finally received Roman citizenship, extending to his wife and his descendants. Through the ‘law of legal marriage’ (ius conubii), also awarded to him at that time, an existing or proposed matrimonial alliance with a ‘foreign’ woman was now fully recognized before Roman law. So now he could live in a family recognized by Roman law for the first time! The citizenship acquired via service in the auxiliary troops helped millions of provincials to become the legal and social equals of Roman citizen who had moved to the provinces after the conquest. These privileges, of which the most important were citizenship and legal marriage, were so important that it is no wonder that many soldiers wanted them confirmed in duplicate. These documents had the form of bronze plaques, so-called ‘military diplomas’. They contained the text of the imperial decree of the honourable discharge of this soldier from military service, as well as the date, the names and seals of a number of witnesses, the personal data of each recipient and his wife and children, his direct and indirect superiors, as well as a list of all troops affected in the relevant province, an extremely important source for Roman military history (Eck and Wolff 1986; Eck 1997 and 2010a; Pferdehirt 2004). The original of this document was posted publicly at the Temple of Minerva in Rome, so the recipient only received a copy.


From the late 1st century, the so-called numeri appeared, ranking below the auxilia (Reuter 1999a). These consisted of 100- to 200-strong guard and reconnaissance units, stationed along fixed lengths of frontier. If such units were mounted, they were called exploratio. They were under the command of a praepositus numeri, often a centurion seconded from a legion. Numeri were used in addition to the alae and cohorts for frontiers or to explore and secure areas beyond the frontiers, particularly in more remote forest regions, like the Taunus and Odenwald in Germany or on the Dacian limes. In contrast to other auxilia, they always seem to have been used in the same province, and always in the same frontier sector; they were not, for example, sent on campaign. This proves that, as local scouts, they were familiar with a particular section of frontier. The names of the numeri were often formed from the nations from which they had been raised, as with, for example, the diverse numeri Brittonum or numeri Palmyrenum. In order to identify a specific unit among the various numeri Brittonum in Upper Germany, the name of a river or a source in their territory was added to the name of the unit. An example is the numerus Brittonum Elantiensium, named after the River Elz, a tributary of the Neckar.


The emperor and the provincial governors were protected by guard units (Fig. 8), whose soldiers were detached from the regular army (Busch 2010). These cohortes praetoriae, introduced by Augustus, guarded the emperor and his family and went to war with the emperor. They originally numbered nine cohorts of 1,000 men, each made up of 900 infantry and 100 cavalry. From the time of Tiberius (AD 14–37), they were based in the Praetorian Camp in Rome and were for a long time the strongest military power in and around Rome.

Augustus also introduced a mounted guard of Germans, the Germani corporis custodes, although their strength and organization are not known. This unit was disbanded under Galba. Only under Trajan was there a mounted guard again, the equites singulares Augusti. Furthermore, there were other special units recruited from troops in.

Rome, such as the speculatores Augusti, evocati, statores, frumentarii, and speculatores legionis. In addition, soldiers of the Imperial fleets from Misenum and Ravenna were reassigned to operate the awnings in the circus and in the theatres.

To these regular military units were added the cohortes urbanae, the city soldiers, and the cohortes vigilum, a kind of military fire service and night watch.

Not until Septimius Severus (AD 193–211) did the military presence of the Praetorians in and around Rome become much stronger. First, the Praetorians were temporarily disbanded and a legion, legio II Parthica, was stationed in Albano, near Rome; then the theoretical strength of the Guard was increased considerably.

In the praetorian frontier provinces without legionary garrisons, there was a ‘guard’ for the governor consisting of around 250 cavalrymen and infantrymen, the equites and pedites singulares, which consisted of selected men from the provincial army. In the provinces with legionary garrisons, the governor’s guard consisted of selected legionaries.

Troops and paramilitary units in Rome during the Imperial period (after Busch 2010)

Theoretical strength of troops in Rome during the Imperial period (after Busch 2010)


From the early Imperial period, there were also local militia units in the provinces: iuniores or iuventus associations are testified, without details of their number, structure and military armament being known. They gained greater importance, especially in the turbulent times of the 3rd century, and were then more frequently attested epigraphically. Thus the inscription on the Augsburg victory altar names populares, unspecified militiamen, as jointly responsible for the Roman victory of 24th/25th April 260 over the Semnones/Iuthungi (Bakker 1993).

The so-called ‘military reform’ of the 4th century AD

With few exceptions, the Roman army – legionary and auxiliary troops – was based along the frontiers in permanent legionary camps, as well as ala, cohort, and numerus forts, from the time of Augustus. Apart from the Praetorians and bodyguards of the emperor, Italy had no military presence; only from the time of Septimius Severus (193–211) was there a legion south of Rome, in Albano. This meant that the military high command had no significant mobile reserves present in the interior of the empire to deploy alongside the frontier army.

In this system, concentrations of military force, such as were necessary for field campaigns or in the defence of larger attacks, were difficult and time-consuming to accomplish, as ad hoc army groups (vexillationes) had to be assembled from the various provincial armies to undertake specific combat missions (Saxer 1967). If the task was completed, the individual components of these vexillationes returned to their regular units. While this approach generally worked until the 3rd century, or the practical-minded Romans would not have kept it, during the 4th century the weaknesses of it became increasingly obvious. At a time when there were often multiple simultaneous external attacks on the Rhine and Danube frontiers by Germans, Sarmatians, and other opponents, and in the East by the Parthians and then by the Persians, this system simply collapsed. The withdrawal of troops from a momentarily seemingly less-endangered western frontier for field campaigns in the East now meant that Germanic opponents recognized the weakness and regularly took the opportunity to attack the frontier provinces. In addition, the wars between rival claimants to the throne often meant that the best troops of the Empire fought each other, often to the point of almost total annihilation, from the time of Septimius Severus onwards.

The first large-scale measures to reform the Roman frontier defensive system and get this problem under control can be detected under Gallienus (AD 253–68). Since the effectiveness of the Persians and Germans was probably that they were mostly mounted, a cavalry formation – which was mobile and stationed in Milan – was set up by the emperor from new units to protect Italy and Rome from threat. They could even catch an opponent if they had already broken through the frontier defences and had penetrated far into the hinterland. In late antiquity, this system was perfected with a functional division of the army (border guard troops in garrisons on the frontier, mobile task forces in the hinterland) and introduced throughout the empire. The older view of this dual system as a new introduction in the context of military reform under Diocletian and Constantine is being increasingly called into question by research. Thus, for example, K. Strobel (2007) and Y. Le Bohec (2010) emphasize the continuous development of the comitatensian or mobile army from the mid-Imperial period onwards. However, fundamental changes in the Roman army arrived in the 4th and 5th centuries AD, but are difficult to reconstruct in detail. In general, the Late Roman military system is much less transparent than those of the Republic and the early to mid-Imperial period. Due to their scarcity, written sources generally play a much smaller role for the military history of late antiquity than for the preceding period; the number of inscriptions generally decreased radically, in other words epigraphic evidence with military implications – which previously constituted the most important source for the organization and distribution of Roman troops – disappeared almost completely. Here, even the text originating in the early 5th century AD, the ‘directory of all offices, both civilian and military in the western parts of the empire’ (Notitia dignitatum omnium, tam civilium quam militarium, in partibus Occidentis), known for short as the Notitia Dignitatum, is hardly a substitute. But at least the units of the frontier army and weapon factories are listed in it.

From at least the reign of Constantine I (AD 306–24), the Roman army was divided in two: there were now a frontier army permanently based in frontier forts, the limitanei or riparienses, and a mobile army operating in the hinterland, the comitatenses. The frontier units were largely maintained along earlier lines, in terms of formation and tactical designation (legions, alae, and cohorts), but their theoretical strength was significantly lower than that of the same units of the early and mid-Imperial period. This can be seen from fort sizes, compared to the early and middle Imperial period.

According to the Notitia Dignitatum, the military command of the frontier troops of the Western Empire lay in the hands of the highest-ranking soldier in this part of the Empire, who held various titles and had diverse areas of competence over the course of time. He was called magister militum [utriusque militiae] (‘master of the army’ or ‘master of all military branches’), or at the Imperial court magister peditum praesentalis (‘master of infantry present [at court]’); after c. AD 370 he was addressed as Illustrious One (vir illustris); the dux limitis (frontier sector commander) reported to him. Occasionally, this post was filled by one person for several provinces, like the military commander of the two Raetian provinces. He bore the title of dux provinciae Raetiae primae et secundae (General of the First and Second Raetian Provinces) with the rank of Admirable One (vir spectabilis).

Diagram showing the hierarchy of the Roman fleets of the early and middle Imperial period (after Pferdehirt 1995)

The Roman navy

The Roman fleet of the Imperial period, like the auxiliary troops of the Roman army, took as recruits free, but legally and socially underprivileged, peregrine residents of the Empire who did not possess Roman citizenship. However, they could gain the coveted Roman citizenship for themselves and their families through military service. However, since naval service was considered more difficult than that of the forces on land and since, with a total of 26–28 years, it was also longer than the 25 years of service for the legions and auxiliary troops, those entering the fleet gained the special privilege of Latin citizenship for themselves from the start – but not for their wives and children. Although this did not offer all the privileges of full Roman citizenship, it was a huge leap forward in legal status for a peregrine provincial. A fleet soldier received full Roman citizenship for himself and his family only upon honourable discharge, after having completed the whole term of service.

Of course, this rule did not apply to the officers who, from the outset, had to possess Roman citizenship. The supreme commander of a fleet, the praefectus classis, came from the equestrian order.

In organization and jurisdiction, the Roman fleet was divided into two parts, with a clear distinction apparent between the sailors and the marines. This went so far that every ship had two commanders, one nautical and one military. The nautical commander bore the title nauarchus on larger vessels, on smaller ships trierarchus; these designations were quite obviously adopted from the eastern Hellenistic area, albeit with a certain change of meaning.

A particular theme in Roman military archaeology – the iconographic and textual sources, and especially the original remains of Roman warships – has recently led to the development of a separate direction in research: the study of ancient navigation. The discovery of numerous shipwrecks in the Mediterranean, but also of warships used on the Rhine and Danube, like the ships from Mainz and Oberstimm, has brought further advances here. In particular, the Museum for Ancient Navigation (Museum für antike Schifffahrt) in Mainz (affiliated to the nearby Römisch-Germanisches Zentralmuseum) has had a major impact in this as an international research institute.

Military crews were equivalent to the centuries of the land army. These consisted of about 80-strong combat units under the command of a centurion. Therefore, there was a marine captain with the rank of centurio classicus. Above all, the sailors were often specialized, there being helmsmen, navigators, a man who was on the lookout in the bow, warning of shoals, a coxswain for the rowers, loadmaster, doctors, and others.

New Strategies of the Third Century Roman Empire I

‘Posterity, which experienced the fatal effects of his maxims and example, justly considered [Septimius Severus] as the principle author of the decline of the Roman Empire.’

Edward Gibbon, The Decline and Fall of the Roman Empire

Historians have argued for decades that Septimius Severus not only contributed to the decline of the Roman Empire but that he may have been the architect of its downfall. Much of this discussion hinges on his military reforms. Seen over the course of succeeding centuries, his changes in military organisation may have been fundamental in shifting the Roman military might from a strategy of static frontier defence to one of central reserve forces.

It remains uncertain, however, whether Severus himself consciously planned to take the Roman army in this direction or whether he was in fact responding to immediate concerns of defence. The army that emerged one hundred years later would be based on a bipartite military organisation, this would differ significantly from the well-known array of legions that spread out along the empire’s frontiers. The frontier of the fourth century Roman Empire would be settled by limitanei border garrisons, while more centrally located mobile field armies (comitatenses) would be ready to respond to threats from any direction.

Between Severus and this new strategic model, however, lay the battles and upheavals of the third century. Nothing was set in stone and nothing could be taken for granted. Historical hindsight induces a calm complacency, but for those living at the time, Rome (‘the world’) was being beaten back, overrun by adversity and faced imminent destruction. Individuals, not history or destiny, would carve out the empire’s future… if it had one at all.

How the Legions Work

In 192 the defence of the Roman Empire was based around thirty legions, dispersed around the frontiers as needed. The legion was a corporate unit, with its own identity, traditions and battle honours. Its men were often fiercely proud of their legion, a relationship enjoyed today between a British soldier and his regiment.

In size each legion was similar, with a manpower of roughly 5,000 soldiers based around ten cohorts. These cohorts were commanded by senior centurions and were each formed up of six centuries. Despite the misleading title, the century was a combat unit of eighty men led by a highly paid centurion. Cohorts then, being six centuries in size, had a typical strength of 480 men. The cohort and the century were the real tactical units of any Roman force. A cohort may be ordered to ‘follow the flag’ to form a vexillation and join a larger unit needing extra manpower.

The eighty men of a century were billeted in ‘tent parties’ of eight men each, these soldiers would be squad-mates, eating and sleeping together, fighting together, sharing a tent on campaign and a set of twin rooms while in barracks. Centurions had their own staff, not only a servant or two, but also junior officers from the century such as the tesserarius (watch keeper), the signifier (standard bearer and unit treasurer) and the optio (the centurion’s second-in-command). This unit proved quite self-sufficient, its men cooked their own meals and had entrenching tools, tents, arms and armour. It could draw mules from the legion to carry rations, equipment and other baggage and operate independently of its parent unit.

Some, and perhaps all, of the legions elevated the status and responsibility of the first cohort. The writer Vegetius reports that men of the first cohort were the tallest men in the legion.1 Instead of six centuries the first cohort contained only five, although its centuries were kept at double strength (170 men under a single centurion, rather than eighty). This meant that the first cohort became a powerful unit of 800 soldiers, a formation that could be used to spearhead assaults. As the cohort of honour, ‘the first’ was no doubt filled with veterans from across the legion and its five centurions must have been the most senior within the regiment.

In command of a legion was a member of the senatorial order, a legatus legionis. He was a man in his thirties working his way from office to office and was aided by a young senatorial officer, a tribunus laticlavius, perhaps in his late teens or early twenties. He may hope to command a legion himself, later on in his career. Third in command was a seasoned centurion of long service, the praefectus castrorum, or camp prefect, responsible for logistics and administration. Like a senior NCO in any modern army, he will have been able to provide valuable tactical advice to the legionary legate. There were in addition, five young tribunes (tribuni angusticlavii) from Rome’s equestrian class within the legion’s headquarters. Without any specific command responsibility, they were given tasks as and when needed.

Each legion was allocated its own troop of 120 cavalry which carried out scouting, long range patrol, courier duties and screening the flanks of the legion if it was called on to march through hostile territory. Of course the cavalry also had its use in battle but typically this involved mopping up the enemy soldiers after the Roman legionaries had forced them to break and flee.

Additional forces were provided by auxiliary units (auxilia). Whereas legions were only open to Roman citizens (and popular with the poor and landless), the auxiliaries recruited non-citizens from recently conquered provinces. The bellicose tribes that had given the Romans so much trouble during the invasion and takeover of their homelands made ideal army material. Gauls, Germans, Britons, Dacians and others provided men for these auxiliary units.

The relationship between legion and auxilia could be compared to that of the International Security Assistance Forces (ISAF) and the Afghan National Army (ANA) in modern-day Afghanistan. Post-Taliban, the ANA was reformed and underwent training along NATO lines, using US uniforms and equipment. Patrols and assaults in Afghanistan have been conducted by both forces in concert, with ISAF troops taking the lead. Like the Roman auxilia, the ANA often provides support during assaults, but it is also able to conduct its own operations. The analogy cannot be stretched too far, but it gives an idea of the relationship and differing status between the two types of troops. A division of labour, trust and responsibility existed between legion and auxilia.

Auxiliaries really were the junior partner in the military relationship. Pay for an auxiliary infantryman was 100 denarii compared to 300 for a legionary, for example. Auxiliary units were based around a single quingenary cohort (around 480 strong) or a double-sized milliary cohort (around 800 strong). This meant they could be moved easily around the empire as needed but it also pre-empted any troop rebellion. An aggrieved ethnic group now fighting for Rome as an auxiliary unit would have little chance against the higher level command structure and massed cohorts of a Roman legion. Auxiliary uprisings were very rare but did occur from time to time. ISAF troops, wary of individual ANA soldiers within their compounds, may sympathise with Roman legionaries who had no choice but to fight alongside men who had until recently been their sworn enemies …

Most Roman cavalry was provided by mounted auxilia, since many frontier peoples maintained a long tradition of horsemanship. These auxilia were organised as quingenary alae (with a strength of 512 men) or milliary alae (with a strength of 768 men).

Following the Flag

Under the early emperors, a legion or an auxiliary cohort would have many duties, from guarding granaries or post houses, to arresting dissidents, conducting patrols, overseeing some industrial activity and so on. Sometimes these duties took soldiers away from their home fort for weeks or months, but rarely were the troops posted outside of the province.

When an emperor was assembling an army for an assault on some foreign power, or if a frontier defence needed shoring up, he could call on those legions close at hand. He would also need to supplement this force with entire units from much further afield. Legio X Gemina, for example, was based in Germany but ordered to join emperor Trajan’s invasion force for his attack on Dacia in AD 101. It did not return home but was relocated after the Dacian war to Pannonia. This legion was one of three in Pannonia that acclaimed Septimius Severus as emperor in 193. The uprooting of an entire legion to some distant battle-front, along with its staff, families and equipment was the way in which large-scale warfare was waged.

As legions became more entrenched within their home provinces and took up the burden of local frontier administration, it became a difficult matter to lift a legion out of its province. Instead a unit might be ordered to contribute a detachment of men for a particular campaign, a detachment that would return home once the war had ended. When the Jews rebelled against Roman rule in 132, for example, detachments from X Gemina marched east to reinforce the Roman army there. Later in 162, Lucius Verus, the co-emperor of Marcus Aurelius, took a detachment of the Gemina into Parthia, far to the east.

By the time of the Marcomannic Wars, this practice of ordering discrete bodies of men to fight for short periods in wars, before returning them to their forts, had become common. The Latin term for such a detachment was vexillatio, from the word for flag or banner: vexillum. These detachments marched under a temporary Roman military vexillum, which resembled a flag fluttering from a crossbar that was suspended from a central pole. It seems that the vexillations were brigaded together to form a more effective fighting force. They would either return home at war’s end or, as happened to some vexillations, the troops would remain within the provinces they had fought in. Some, such as the vexillatio equitum Illyricorum, even became fully functioning units in their own right.

A typical combat detachment would normally be composed of one or more cohorts (c. 480 men) each of which could be separated from its parent legion easily and also take advantage of its internal six-century organisation. These centuries retained their own staff and had the ability to work independently. Together as a cohort the centurions commanding the centuries provided excellent leadership and an officer would be assigned to lead the detachment. Although his title was praepositus, he was most likely one of the five young tribunes (tribuni angusticlavii) that ordinarily performed staff functions within a typical legion. Assignment to lead a detachment could be great opportunity in the career of a young tribune, eager to make his mark.

Marcus Aurelius, the philosopher emperor, struggled to field enough soldiers using the system of vexillations alone. He was forced to create three new legions, Legio I, II and III Italica, but as tradition dictated, two of these were then settled into legionary bases on the frontier. Within five years these new legions were themselves sending out vexillations to places like Salonae, where detachments helped fortify the city against barbarian attacks.

There was no other easy way to mobilise troops for some new and troubling crisis. An emperor could either move entire legions, gambling that the frontier they protected would remain peaceful in their absence, or he could call on numerous individual detachments, which sometimes spread a legion out across more than one continent. During the crisis years of the third century attacks on the frontier became simultaneously more frequent and more widespread, the constant need for quick reaction forces necessitated the use of the vexillation. It could be mobilised rapidly and arrive at the frontier hot-spot to fight alongside other vexillations under a temporary commander. During the early third century vexillations sent to garrison frontier forts might expect to be deployed for up to three years. For those detachments engaged in field operations, however, a return home might be many more years away. Warfare in this chaotic century was almost constant and a full-strength vexillation was always needed somewhere along the frontier. A number of detachments spent so long operating in the field that they became, in effect, independent combat units.

Did Severus have an answer? He certainly moved legions around to help leverage the manpower he needed for his attacks on Parthia in 197 (and later in 208 on the north of Britannia). He also made use of vexillations to supplement his forces. Did his newly created Legio II Parthica, based in Italy, constitute a new type of military reserve? Although there is no evidence that Severus mobilised its troops to fight on the frontiers, his son, Antoninus, certainly did take large numbers of the legion eastwards to battle against the Parthians.

The New Reserve

The first Christian emperor of the Roman Empire, Constantine the Great, had at his command a mobile field army supplemented by entrenched frontier forces, or limitanei. While the limitanei garrisons slowed an enemy invasion but did not stop it, the field army was tasked with rushing to the region to prevent the barbarian force from penetrating any deeper into imperial territory. This was defence ‘in depth’ that planned to catch the enemy after it had crossed the frontier. It was the way of the future and a new system of military organisation that would be matched against the almost overwhelming barbarian invasions of the fourth and fifth centuries. Although Constantine ruled more than a hundred years after the time of Septimius Severus, it is possible to see the very start of this revolutionary new concept within Severus’ own strategy.

Mobile armies, independent of fixed legions, are often seen as a feature of the Late Roman era, but the historian Michael Speidel noted that ‘the field army is, in a sense, as old as the units stationed in Rome.’ The Praetorian Guard had been Rome’s garrison during the first two centuries of imperial rule but it was rarely deployed to a battle-front. Septimius Severus changed all that, in effect turning the Guard into Rome’s first mobile (or ‘imperial’) field army. As we saw in chapter one, the emperor opened up recruitment to veterans of his Pannonian legions as a reward for loyal service. This also had the effect of elevating the Guard to the status of an elite fighting unit; members were all now battle-hardened veterans. One Praetorian proudly proclaimed on his tombstone that ‘he had served in all the expeditions’.4

At a standing size of 10,000 soldiers and without the onerous administrative duties of units on the frontier, the Praetorian Guard had become the largest combat-ready force within the empire. It remained so throughout the third century and when paired with the new Severan unit, Legio II Parthica, became what was essentially the first effective imperial field army. The II Parthica was a regularly-sized legion of between 5,000 and 6,000 troops, but like the Guard, had no other duties. It was a lean fighting unit with an effective manpower greater than many other legions. Without other duties to tie it up, the II Parthica was always ready to march and to fight. Since it was always available, the II Parthica became the personal legion of the third century emperors and the unit’s commander even became a member of the imperial retinue. In that sense, then, it was not a true independent field army but instead an imperial fighting unit that could provide a reserve of troops for other legions if necessary.

There were a number of other smaller units available at Rome that added to this new reserve, including one of the six Urban Cohorts of military police that patrolled the streets of the capital. Severus increased their membership which meant that a single cohort could contribute 1,500 soldiers to the army reserve. We know at least one cohort could be spared for combat duties after the presence of Urban Cohort XIV was recorded at Apamea in Syria, where it had fought alongside II Parthica.

A number of mounted units had been garrisoned in or around Rome for some time and these may also have bolstered the strength of the Severan army. Foremost among these cavalry units was the imperial guard cavalry, the equites singulares Augusti. Just as he had with the Urban Cohorts, Severus increased the membership of this elite force, doubling it from 1,000 to 2,000. To these he probably added many of the Moorish cavalry that had surrendered to Severus after the battle of Issus in 194. Together with the Mauri auxiliaries that already garrisoned Rome, this light cavalry force numbered around 2,000 individuals and it fought in battle with Antoninus, the eldest son of Severus who was to succeed him. Finally, the ancient writer Herodian recorded that Abgar IX, king of the defeated eastern kingdom Osrhoene, supplied Severus with a force of (horse?) archers for his invasion of Parthia in 197. These cavalrymen then joined the new imperial reserve and may have been garrisoned at Rome within the castra peregrina.5

Amassed together, the Severan reserve may have totalled around 21,500 soldiers, which provided Severus and his successors in the third century with an unprecedented combat force. Vexillations from other legions would then attach to this military core in order to create an expeditionary army able to invade Parthia or tackle the hostile German tribes on their own territory. The variation in troops or detachments assigned to the army depended of course on the location of the threat and the availability of manpower. Emperor Maximinus, for example, raised a unit of German cavalry whilst on campaign in the north, in order to augment his expeditionary force.

Cavalry was proving increasingly valuable. In wars of the past, emperors had time to assemble a large army by marching legions to a troubled province or weak frontier. Once the troops were assembled the invasion would be launched. Often this invasion was either one of retribution for some recent enemy attack, or more likely a pre-emptive strike against a rising power. Rome no longer had the time for this kind of strategy. What the third century crisis needed was mobility and a rapidly reacting force that could attempt to deal with constant raids and invasions on many different frontiers simultaneously. Having an army almost permanently in the field led personally by the emperor addressed this new demand, as did a recognition of the value of cavalry.

Soldier emperors had to lead from the front, which meant that Rome saw less and less of them. Meanwhile, well-fortified frontier cities that lay on good communication routes behind the embattled frontiers began to serve as ad hoc imperial centres. Colonia, Treverorum, Aquileia, Sirmium, Mediolanum, Vindobona … all saw as much, if not more, of the emperor and his retinue than did Rome. Emperors could not leave this powerful military force in the hands of a trusted officer. This was to become a factor in any military deployment that had been relatively uncommon prior to the third century. Back in the first century AD the emperor Claudius, for example, had been able to leave the conquest of Britain to his general Aulus Plautius without fear that the general might suddenly turn the invasion force toward Rome.

The third century would illustrate time and time again that there were no longer any trusted men out there. A cycle of civil wars spanned the century as a long line of usurpers rose to seize the throne for themselves. Many emperors died violently and most of those deaths were the result of assassination. However, it was easier to gain power in the third century than it was to hold on to it; the reign of most of these emperors lasted for no more than a few months. The year 253, for example, saw the emperor Trebonianus Gallus murdered by his own troops as he prepared for battle against an usurper, Aemilius Aemilianus. Within months one of Aemilianus’ own generals, Valerian, declared himself emperor and marched his armies south to seize the throne. Confrontation was avoided when Aemilianus’ own army lynched him near Spoleto in October. While Gallus had reigned for just over two years, the rule of Aemilianus had lasted only eighty-eight days.

New Strategies of the Third Century Roman Empire II

Cavalry Strike Force

It has long been thought that Valerian’s son, Gallienus (reigned 260–268), created a powerful new, mobile and independent cavalry force that presaged the cavalry-dominated field armies of the fourth century. The new cavalry unit was named the equites Dalmatae and was recruited from the province of Dalmatia (located along the Adriatic coast) around 255. After fighting in Germany, it was based at Mediolanum (modern Milan) from where it was able to assist with the defence of the north Italian plain from an invasion by Alemanni or (more likely) pretenders to the throne.

With few reliable historical accounts from this period, evidence has to be gleaned from other fragmentary sources. The theory that Gallienius’ cavalry unit formed Rome’s first mobile field army was created by the eminent scholar Emil Ritterling in 1903, assisted by the work of the German numismatist Andreas Alföldi. Although once widely accepted, this theory has since been heavily criticised.6 More likely, the equites Dalmatae as well as two units of mounted Moorish javelin men (the equites Mauri) and Osrhoene horse archers, simply served as supporting cavalry forces. There is little evidence that they were at all independent or enjoyed the command of a senior general; they acted, as cavalry had always acted, as a powerful skirmishing force. Their creation shows that cavalry was being used in greater numbers, but not that it was independent. The cavalry was most successful operating in conjunction with the infantry and as lightly armoured skirmishers they could not conduct the kinds of pitched battles that the heavy fourth century cavalry would later do at the battles of Adrianople, Chrysopolis and Campus Ardiensis. Cavalry in the fourth century would focus on heavily armoured cataphracts capable of shock attacks; nothing like that existed in any number during the third century.

The nature of the threats to Roman security throughout the third century necessitated the development of the available cavalry forces. Gallienus expanded his cavalry and organised it into new units of equites charged with the job of finding out the whereabouts of the enemy and goading it into the path of the main imperial army. These equites formations were wide-ranging, and enjoyed the freedom of an extended security force, yet did not constitute anything like a fourth century field army. Their existence, however, illustrates the strategic problems faced by emperors of the day. Threats were emerging continually, on all the major frontiers with greater and greater frequency, wars and incursions overlapping so much that the legions were being worn thin, propped up by vexillations, unable to move to another danger area for fear of leaving their own borders defenceless.

The Threat

From 226 onwards, the kingdom of Persia became a major thorn in the side of Rome, bringing death and destruction to the eastern provinces on an unprecedented scale. Meanwhile, renewed pressure from the German tribes from across the Rhine threatened the safety of the city of Rome itself. The third century was becoming a turbulent time of frontier crises and internal struggles … and the fracas would be joined by the game-changers, the new people emerging from Russia: the Goths.

While the reasons behind the attacks on the frontiers are complex (and beyond the scope of this book) there is little doubt that Rome itself was in some measure to blame for their intensity. Ctesiphon, the Parthian capital, had been sacked twice in the second half of the 2nd century. Parthian military prestige and fighting ability had taken a hammering and had helped to create the perfect situation at home for Iranian ‘regime change’.

Along the Rhine frontier Rome had sought to keep the peace for centuries through tribal dissension and the promotion of client chiefs. After the Marcomannic Wars these smaller tribes had begun to co-operate, finding a new strength and bargaining power when allied, rather than divided, as Rome would have wished. It was clear that as soon as some of the tribes entered into mutual confederations, the remaining tribes would hurry to do the same. Tribes familiar to the earlier emperors, like the Cherusci, for example, were subsumed within these new confederations, the Franks, Alemanni, Saxons and Burgundians. Along the Danube equally powerful tribal alliances were being created. It had been the intensity and duration of Rome’s counter-attacks during the Marcomannic Wars that had forced the tribes to react in this way.

The Persians

On the thirtieth day of the month of Xandikus of the year 239, the Persians descended upon us.

Graffito from a house in Dura Europus.

Parthia had endured and thrived throughout the long rise of Rome. Heirs to the ancient Persian Empire of Darius and Xerxes and Alexander the Great, the Parthians had once been a tribe of steppe nomads that had crossed into Iran from the Kara Kum desert. The society ruled by the Parthian elite (the Arsacid dynasty) was feudal in nature, chieftains defending small regions who owed allegiance to provincial nobles who then looked to the king. All of these nobles fought on horseback during war, the richest as cataphracts, which were heavily armoured cavalrymen fighting with long spears, axes and swords and riding fully armoured horses. Poorer nobles fought as horse archers, a superb class of warrior that was fast moving, able to fight from a distance and that was difficult for the Roman legions to come to grips with. Cavalry defined the Parthian (and later Persian) method of waging war.

With no full time professional army available, military campaigns involved the mobilisation of local nobles who brought with them their own retinues, peasant levies and mercenary forces of hill-men and desert nomads. From time to time these nobles were at war with one another and civil war would split the feudal system, just as it had during Caracalla’s reign.

The ancient Persians who had once ruled the Iranian plateau and beyond were once again in control of the region following Ardashir’s victory over the Parthian king. This new dynasty, the Sassanian, would continue to challenge Rome in the east for another four centuries. Following the dynastic change would come a restoration of Persian noble families to power, a renewal of old Persian values, religion and art. Institutions like the unit of elite warriors, the Immortals, flickered into existence once again. In warfare the Persians inherited the Parthian feudal system and its reliance on cavalry as the main striking force. There is some suggestion of a professional and skilled military corps since the Persian army now begins to besiege enemy cities, something the Parthians could never attempt.

Of greatest worry to Rome was Persia’s new found aggression. The Arsacid dynasty of the Parthians had been happy to maintain a status quo, defending against Roman attack when necessary and attacking in retaliation. The new Sassanian dynasty had in mind to restore the Persian Empire to its ancient glory and that meant sweeping Rome’s eastern provinces away in order to replace them with Persian satrapies.

(Ardashir) became a source if fear to us; for he was encamped with a large army against not Mesopotamia only but Syria also and boasted that he would win back everything that the ancient Persians had once held as far as the Grecian Sea.

The Germans

‘(a German) thinks it spiritless and slack to gain by sweat what he can buy with blood.’

Tacitus, Germania 14

Occupying the lands on the far bank of the river Rhine, lands of swamp and trackless forest, dwelt the German tribes. For the Romans, Germania represented a region that could not be conquered. Attempts had been made of course, emperor Augustus had wanted to push the frontier forward, from the river Rhine to the Elbe. His generals made war on the Germans, pushed the Roman forces deep into the dark forests until in AD 9 three legions were destroyed in the Teutoburg Forest. It was a military disaster from which Roman morale never recovered. The frontier was pulled back to the Rhine and (further east) to the Danube and there it remained. Raids, punitive expeditions and outpost forts would carry Roman power into this wild region, but it always remained ‘beyond the frontier’.

German physique and martial spirit impressed and frightened the Romans. They were a tribal people, owing fealty to a local chief who led his warriors into battle to bring his tribe glory, wealth and security. His position was subject to change, the tribal assembly of elders (the thing) could always call for a new leader and so chiefs remained in power if they could secure success in war and the loyalty of their warriors. These chiefs or kings grew accustomed to allying together since large confederations could achieve more than one tribe alone. These super-tribes were the cause of the Marcomannic Wars that so threatened the empire in the 170s. Throughout the third century, German tribes like the Franks, Alemanni, Juthungi, Marcomanni, Quadi, Suebi, Burgundi, Chatti and others were poised to launch themselves against the Roman defences. Two factors drove the tribes onward, the first was booty and prestige that a king gained from raiding Roman territory and the second was the relentless pressure on tribal lands from tribes further east. The greatest threat from the German tribes was their relentless aggression. Year after year they would attack the Roman frontier, pushed onto the defences by the billiard ball-like repercussions caused by the movements of distant nomadic movements far away on the Asian steppe.

In battle the elite German warrior was a swordsman, protected by a shield but little, if any, armour. Poorer German fighting men were similarly unprotected but carried spears, javelins, axes or bows. Helmets and ringmail shirts were certainly available to members of the mounted nobility. From the second century onwards more and more Roman swords were being used by the tribes and a significant number have been found in ritual bog deposits, such as those at Vimose in Denmark and Thorsberg in Schleswig-Holstein, Germany.

The Sarmatians

The Marcomannic Wars heralded the very beginning of the barbarian attacks which resulted in the depredations of the third century and the eventual fall of the Western Roman Empire in the fifth. The term ‘Marcomannic War’ is a modern creation, those fighting it called the conflict the German and Sarmatian War (bellum Germanicum et Sarmaticum).

The Sarmatians were a federation of horse-riding nomad tribes that had occupied the southern Russian plains for several centuries. By the reign of Marcus Aurelius several sub-tribes, including the Iazyges and Roxolani, had moved westwards into Europe and settled in the lower Danube valley. Although they had established farming communities, it seems the Sarmatians retained a semi-nomadic lifestyle. Ammianus Marcellinus writes that they: ‘travel over very great distances chasing others or themselves turning their backs, being mounted on swift and obedient horses and leading one or sometimes two, so that changing may maintain the strength of their mounts and their vigour be renewed by alternate rests.

From the Danube region they joined with the German tribes in their attacks on Roman cities. Pressure from the southerly migration of east Germans (the Goths) moving south into the Black Sea region intensified the Sarmatian pressure on Rome. Sarmatian successes have been credited with the tactical innovation of the cataphract, where man and horse are completely covered in ring-mail or scale armour to create a heavy cavalry striking force.

An aristocratic warrior elite (the argaragantes) ruled the tribes, whilst the majority of the work was done by the serf-like limigantes. Tribes were nomadic, moving from place to place on horseback or on the covered steppe-wagons, the kibitkas; they were also warlike, structured according to client and vassal relationships, in a very similar way to the Germans. Powerful warlords could attract significant followers with smaller clans and sub-tribes eager to share in glory and gold. Continual warfare between the Sarmatian tribes and the Danubian legions of the late second century brought the two forces into close contact on a regular basis. There would be an inevitable exchange of fashion, weaponry and tactics because of this. It would not just be Romans that would emulate the expert horsemen of the Sarmatian tribes, the Goths too learnt much from these people.

The threat from the Roxolani and Iazyges came from their perfection of the heavy cavalryman, something relatively new to Roman warfare. A Sarmatian warrior noble wore a helmet and a coat of armour (either scale, ringmail or ‘locked scale’) that often covered his arms and legs. Not only that, but his horse was protected by a similarly armoured helmet (chamfron) and trapper. Equipped with a long and heavy two-handed lance, the rider could participate in a charge that would scatter light infantry or cavalry. This was an innovation that would later be perfected by the chivalric knights of the High Medieval period.

The Goths

From Scandinavia, centuries before the time of Septimius Severus, a number of east German tribes began a slow migration southward through Poland and Russia which eventually brought them into conflict with the Sarmatian tribes and, ultimately, Rome. Goths and Vandals would eventually carve up the Western Roman Empire between them, but, in the third century they were settling in Dacia and Thrace on the northern banks of the river Danube. With much in common with German tribes like the Quadi and Alemanni, the Goths fielded swordsmen and heroic noble warriors in battle, supported by an army of levy farmers carrying spears, javelins and axes. Just like their cousins on the Rhine, the Goths were known for their ferocity in battle.

Although there were many similarities in language, house building and in the gods they worshipped, the Gothic and Vandal tribes had spent many years on the Russian plain rubbing shoulders with the Sarmatians. They and some of the German tribes involved in the Marcomannic Wars (such as the Quadi) adopted Sarmatian ‘customs and arms’. Weapons decorated with Sarmatian animal art became popular amongst warriors; nomadic sword pommels, some be-jewelled with red garnets, became highly prized.

It was the famous horse-skills of the Sarmatians, though, that the Goths took for themselves. Although the German tribes of the Rhine and Danube had always utilised cavalry, it was in the time-honoured fashion: an unarmoured horseman throwing javelins or equipped with a spear and shield ready to ride down fleeing infantry or harass a formation of swordsmen. Gothic formations, in contrast, typically had a greater proportion of horsemen and consequently were far more mobile. Still, the Gothic economy was metal-poor, few warriors wore armour or helmets and few wielded swords and many of the swords found in barbarian graves differed little from the Roman long-sword (spatha).

In the third century the Goths reached the Black Sea coast and, determined to drive southward into rich Roman lands, they created an ad hoc naval force of commandeered ships to begin a campaign of piracy in the Aegean Sea (268). This was a shocking new development for the Roman military which had not seen seaborne raiding on this scale for centuries. The Aegean served as a highway that unfortunately brought the raiders deep into the vulnerable heart of the Roman Empire, the mare Nostrum (‘Our Sea’). These audacious attacks, as well as the raids of the Alemanni, Juthungi and Marcomanni into Italy, profoundly affected the strategic thinking of the Roman hierarchy.

Rise of Septimius Severus I

Septimius Severus and his men contemplating the corpse of his rival for the throne – after the first victory in the Battle of Lugdunum.

‘“You have trained under actual combat conditions in your continuous skirmishes with the barbarians, and you are accustomed to endure all kinds of labour. Ignoring heat and cold, you cross frozen rivers on the ice; you do not drink water from wells, but water you have dug yourself. You have also trained by fighting with animals, and, all in all, you have won so distinguished a reputation for bravery that no one could stand against you. Toil is the true test of the soldier, not easy living, and those luxury-loving sots would not face your battle cry, much less your battle line…” After Severus had finished speaking, the soldiers shouted his praises, calling him Augustus … and displaying the utmost zeal and enthusiasm for him.’

Herodian II.10

While chill February winds whipped around the towers and wall-walks of the legionary fortress, an old man lay dying in the luxuriously furnished house that belonged to its commander. He was in his sixties, yet he was still strong-minded, ebullient and able to talk with both his advisors and his two attentive sons. The old man was Septimius Severus, emperor of Rome. He was far from that city, living with his vast staff of advisors and courtiers, at the centre of the fortress in Eboracum, northern Britannia. Here 5,000 soldiers lived and worked, and were currently resting after fierce fighting in far flung Caledonia. But Severus liked to be surrounded by soldiers, even on his death-bed he would have found the idea comforting. It was the common men of the legions that had elevated him to the throne, followed him into battle and criss-crossed the empire to fight for his glory and his favour.

Even though these soldiers would die to preserve their emperor’s life, there were doubts about others who stood in his bed-chamber. Dio Cassius, a senator and advisor on the campaign, remembered hearing rumours that Antoninus, the emperor’s eldest son, had tried to hasten his father’s death. Another historian, Herodian, stated bluntly that the treacherous Antoninus had actually bribed the court physicians to bring this about.

With death clutching at him, Septimius Severus had a final meeting with his squabbling sons. Both had been proclaimed as heirs and joint co-emperors, but both were intensely fearful that when the time came the other would seize the throne for himself. Dio relates to us ‘without embellishment’ the emperor’s last words of advice to his sons. The secret of his success in war, justice, politics and administration was summarized simply with the advice: ‘agree with each other, give money to the soldiers, and scorn all other men.’

There was little chance of his sons getting on, as events later that year would show, but his last two recommendations were ruthlessly implemented by Antoninus and by successive emperors throughout the third century. Simply put, Severus was telling his sons to lavish money and attention on the legions in order to secure their loyalty. He had done this himself in order to fight off rivals in a civil war. Severus could not call on dynastic loyalties, he could only call on the military barrack-room loyalties of soldiers who had served under him as governor. But those loyalties were always fickle, and maintained by gold and battlefield plunder. To retain the throne he had learnt to cultivate his relationship with the legions in a way that no emperor had done before. He dearly hoped that his successors would do as well in the dark days that were to come.

On 4 February 211, Lucius Septimius Severus, the twenty-first emperor of Rome died. The dynasty he established would last another twenty years before chaos and turmoil would reign…

Legions on the Danube

The source of emperor Severus’ power came from the legions, but more specifically it came from the legions stationed on the Danube frontier. This set of provinces (Raetia, Noricum, Pannonia and Moesia) bound both the eastern and western halves of the empire together. They formed, along with their legions, a vital bulwark against which the belligerent tribes of Dacia and Germany crashed. Its legions were motivated and battle-hardened, and crucially for the fate of any would-be emperor, there were a lot of them.

Forty years of warfare on this Roman border had resulted in a massive build-up of military might. Further west the river Rhine acted as another frontier barrier and legions were also encamped there, ready to repulse frequent raids by German tribes. As pressure from northern tribes like the Quadi, Marcomanni, Naristi and Iazyges intensified, so did the Roman build-up. The Danubian army soon became the largest in the empire. During the on-going civil wars that would erupt throughout the third century the candidates that competed so violently for the throne more often than not were promoted by the soldiers garrisoned on the Danube. Maximinus I, for example, was an ex-legionary, risen through the ranks of a Danubian unit and he gained the support of his fellow-soldiers. From humble origins he become emperor of Rome. It was obvious that these legions held real power; at this crucial cross-roads in ancient history the fate of the empire rested on their shoulders.

It had not always been so. Emperors prior to 162 had only to deal with the German threat across the Rhine, and did so with a military force equal to the task. The river Danube flowing east formed a natural frontier that had been lightly protected, considering its length, and this had been up till now adequate protection. Indeed a new province, Dacia, had been carved out of barbarian territory across the Danube by emperor Trajan. In 162, however, and for a number of years afterwards, Germanic tribes invaded Roman territories, including the Danubian province of Raetia. Marcus Aurelius had two new legions recruited around 165 as an emergency measure, these would become Legio II Italica and Legio III Italica, garrisoned in Noricum and Raetia respectively.

The attacks worsened. In 166 and 167 tribes called the Langobardi, Ubii and Lacringi invaded Pannonia, whilst the Vandals and Iazyges attacked Dacia, killing the governor there. Marcus took his new legions northwards in 168 and so began a protracted campaign against the new barbarian threat. During these wars the barbarian armies crossed the Danube and ravaged parts of the empire, the Costoboci reaching as far south as Eleusis in Greece. Balomar, king of the fierce and well-organised Marcomanni even defeated 20,000 legionaries at Carnuntum in 170 before marching south into Italy to besiege the city of Aquileia. The Roman counter-offensive included both diplomacy and force, and by 180 most of the warring tribes had either been won over or subjugated.

In 180 Marcus Aurelius died while on campaign against the Quadi. His son Commodus had no interest in fighting the war and he left his generals, including Pescennius Niger and Clodius Albinus, to continue it in his absence.

A decade of intense warfare on the doorstep of Italy had shown how vulnerable the empire was to a concerted attack. Yet these Marcomannic Wars were to be but a foretaste of the future barbarian migrations that would end with the collapse of the western half of the empire three centuries later. The threat to Rome was soberly understood, however, resulting, by the end of the Marcomannic Wars, in half of the empire’s military force being stationed behind the Rhine and the Danube. This constituted sixteen out of the empire-wide total of thirty legions.

It was in the year of Marcus Aurelius’ death that a thirty-five-year-old senator from North Africa, Lucius Septimius Severus, gained his first military command. Septimius Severus took up the office of legate, the commanding officer in charge of Legio IV Scythica. Severus would later fight off opponents to become emperor himself, but while in Syria he made contacts, gained valuable experience and may have met his future wife, Julia Domna.

The IV Scythica was one of three legions in Syria, which was the crucial eastern province which held at bay the might of the belligerent Parthian Empire. Governing this wealthy, eastern province was Helvius Pertinax who will have worked closely with his three legionary commanders, including of course Septimius Severus. Legionaries of the IV Scythica will have visited forts and garrison towns along the eastern frontier, including the city of Dura Europus. It is likely that Severus, too, inspected these garrisons, to check on their preparedness should the Parthians choose to over-run the frontier during his time in office.

As commander of the most prestigious of the Syrian legions, Severus may even have been acting governor for a short time. Pertinax, Severus and hundreds of men like them across the empire were of the senatorial class and not soldiers by birth. They competed for better and more prestigious public offices, both administrative and military, in their pursuit of status, wealth and respect. Pertinax, when he was around Severus’ age, had secured for himself command of the Roman fleet on the Rhine, followed soon after by promotion to chief financial officer (procurator) of the Dacian province. The much younger Septimius Severus was similarly eager to climb the ‘ladder of honours’ in search of fame and fortune.

Both Pertinax and Severus later received the governorship of provinces in the western half of the empire, the former of Britannia, the latter of Lugdunensis (southern France). During Septimius’ tenure as governor his wife died and, in 187, he made contact with the high priest of Emesa in Syria to ask for the hand of one of his two daughters in marriage. This was Julia Domna, who sailed to Lugdunensis in order to marry Septimius Severus in the summer. By 192 Pertinax had risen to the position of Prefect of the City and then to consul of Rome in partnership with the young emperor Commodus. Severus, meanwhile, had been made governor of Upper Pannonia. Such an appointment was unexpected. This province, which lay along the vulnerable Danubian frontier, was home to three tough battle-tested legions and no large troop concentration lay nearer to Italy. The command of such a crucial concentration of legions had rarely been given to men who had not earned that position first through the successful governance of several other key provinces. Almost simultaneously Severus’ brother, Septimius Geta, was appointed governor of Lower Moesia, another key Danubian province with two legions of its own. Responsible for the appointment of Septimius Severus was the new commander of the Praetorian Guard, Aemilius Laetus. Perhaps it was no surprise that he hailed from North Africa too, one of a growing number of North African Romans of influence and power within Commodus’ government.

North Africa was not some backwater of empire at this point, it was a thriving region that provided a large proportion of Rome’s grain. Over three centuries earlier the powerful city of Carthage had dominated North Africa and fought three wars with Rome for control of the western Mediterranean. Carthage had been defeated and not just defeated but dismantled and destroyed, its cropland salted and cursed. Over the past three centuries however, newly established Roman provinces in North Africa grew and steadily developed. By the time of Marcus Aurelius, educated and wealthy Roman Africans were reaching great heights, whether they were descended from Italian settlers or old Carthaginian notables.

It may be that Laetus was indeed motivated by native loyalty, or perhaps he simply chose the best man for the job. Whatever his motivations, his choice had extraordinary repercussions on the fate of the empire and on the legions that protected it.

Severus Takes Rome

Commodus, son and heir of Marcus Aurelius who had fought so hard to prevent the northern frontiers from being overrun in the Marcomannic Wars, was a vain, cruel, paranoid fantasist about which none of the ancient writers had anything good to say. There had been several failed plots against his life, it was only a matter of time before one of them would succeed. The Prefect of the Guard, Laetus, and the emperor’s chamberlain, Eclectus, were instrumental in the assassination of Commodus on New Year’s Eve 192. When the poison he was tricked into consuming merely made him ill, the athlete Narcissus was sent in to finish the job by strangulation. One ancient source implicates another influential individual in the murder: Helvius Pertinax. As consul of Rome it was Pertinax who now stood forward to claim the imperial throne. He made a speech within the walls of the Praetorian camp which was the home of the imperial bodyguard. Offering each soldier 12,000 sesterces and announcing that Commodus had died suddenly of natural causes, he asked for the loyalty of the Praetorian Guard. There was hesitation and a little resistance but the troops eventually came around to Pertinax and acclaimed him emperor. Without their support he stood no chance since the Praetorians had gained a reputation in years gone by as masters of the throne. Several emperors owed their good fortunes (and lives) to the whim of these imperial bodyguards. Past emperors Domitian, Otho and Claudius all owed their places on the throne to the actions of the Guard, while the emperors Galba and Vitellius died at the hands of disgruntled Praetorians. When emperors passed on the empire to a nominated successor the Guard had been happy to transfer its loyalty to the new incumbent, whether a blood relative or an adopted heir. In times of dynastic uncertainty, however, the Praetorians were keen to impose their will, or at least receive some kind of payment for their loyalty.

The elevation of Pertinax to the imperial throne proved to be one of those times of ‘dynastic uncertainty’, and although the Guard had been bought off, the loyalty that it purchased would not last for long. The sixty-six year-old emperor tried to change too much, too quickly and crucially attempted to curb some of the excesses of the Praetorian Guard. Resentment against Pertinax grew quickly with the inevitable result that the Guard turned against him. On 28 March three hundred soldiers burst into the imperial palace on the Palatine Hill to challenge the emperor. Despite his attempts to appease them, the Praetorians killed him with their swords. His reign had lasted only eighty-seven days.

The uncertainty created by Commodus remained, there had to be an emperor, but whoever stepped forward had first to deal with the fickle Praetorians. The soldiers returned to the Praetorian Camp fearful of the public reaction, no obvious candidate existed for them to elevate to the purple … and so heralds on the walls of the camp announced the public sale of the throne and not one, but two buyers came forward! Of the two, Flavius Sulpicianus (Pertinax’s father-in-law) and Didius Julianus (a wealthy and respected senator), it was the latter who won the auction. However, the Praetorian’s choice did not prove popular with either the people, the senate or, in the end, the Praetorians themselves. They soon tired of Julianus who did not appear to have the means to honour his lavish promises.

Other candidates for the throne had declared themselves upon hearing the news of the death of Pertinax. Yet these candidates had nothing to do with the sordid auction within the Praetorian Camp, or with attempts to flatter or bribe the imperial bodyguard. These three claimants to the throne were governors in provinces that were home to powerful military contingents and all had a good chance of seizing power. The governor of Syria, Pescennius Niger, was proclaimed emperor in mid-April by the four legions under his command. Later that month Clodius Albinus, the governor of Britannia, also claimed the throne. He had three legions to back up his claim. However, a candidate with some serious military backing had already emerged. Septimius Severus was governor of Upper Pannonia and proclaimed emperor by his troops on 9 April, barely two weeks after the murder of Pertinax. Not only did Severus enjoy the loyalty of the three legions under his provincial command, he had also managed to secure the support of all the legions on both Rhine and Danube frontiers. This amounted to a combined force of sixteen legions, should he dare to mobilize them all.

Having the strongest hand in the game and being the closest to Rome, Severus marched on the capital. Didius Julianus, with the nervous support of the senate, made attempts to defend the city from attack, but with little real success. As Severus and his legions approached the city the senate hastily passed a motion that sentenced Didius Julianus to death and it also bestowed divine honours on the dead emperor Pertinax. Its membership was well aware of the friendship between the murdered emperor and the approaching general. Julianus was summarily executed by an officer; he had ruled Rome for only sixty-six days.

Severus and his army entered Rome without opposition. He was now emperor of Rome and he took the name of Pertinax as part of his own imperial title. What did the Praetorian Guard do about this turn of events? By the time Severus crossed the city boundaries, the Guard had already been disbanded. He knew full well that although the imperial bodyguard might be overawed by the number of troops he had brought with him to secure his claim, months or years down the line they may have a Fate in store for him not too dissimilar to the one they had meted out to Pertinax. Of course Septimius Severus had to be seen to punish the murderers of Pertinax and that was quickly achieved – the men involved were surrendered to him.

To deal with the Guard, he had to be clever and avoid an armed confrontation. Severus asked the Praetorians to pay homage to him in ceremonial dress (that is in off-duty attire, without swords, helmets or armour). When they paraded outside Rome in front of him, Severus then ordered his loyal troops to strip the Praetorians of their military belts, their daggers, uniforms and military insignia. All of the assembled Praetorians were formally discharged and instructed never to set foot in Rome again. The cavalrymen had to let their horses loose, although one horse followed its rider in a stubborn refusal to leave him. The Praetorian was forced to kill the horse and then himself. Thus the Guard was disbanded without a fight.

Rise of Septimius Severus II

The Roman Empire in 210 after the conquests of Severus. Depicted are Roman territory (purple) and Roman dependencies (light purple).

East and West

Writers sympathetic to Severus claim that the people of Rome celebrated his entrance into the city with garlands, burning torches and incense. The more clear headed Historia Augusta records how the new emperor brought his legions with him, first he made sacrifices at the Capitol, then he moved on to the imperial palace. The thousands of troops had to be billeted across the city in temples, porticoes and shrines, and it appears that they behaved badly, taking what they wanted by force and threatening to lay the city waste.

Matters of state were rapidly dealt with and coins were issued. It must be remembered that for any new emperor coinage acted as a tool of propaganda, and allowed the newcomer to advertise his authority and legitimacy to the man on the street. There was little time to waste in Rome, however, Severus had two rivals for the throne itching to replace him. The first was governor of Britain, Clodius Albinus, whom Severus had already contacted and appeased with a share of the imperial throne. Technically now there were two emperors both issuing their own triumphant coinage, yet both knew the day would come when they would have to meet on some remote battlefield to fight for the throne.

Of more urgent importance was his other rival, Pescennius Niger, the governor of Syria who had been acclaimed emperor by his troops but who had remained in Antioch to gather support and build up his army. Less than thirty days after arriving in the capital, Severus and his armies were hurriedly marching east to intercept Niger’s forces at the earliest opportunity.

Battles between the two forces occurred throughout western Anatolia at Perinthus, Cyzicus, Nicaea and at least one of the passes through the Taurus mountains. By fortifying these passes Niger hoped to protect the northern flank of Syria and his capital at Antioch. Beaten back, he was forced to retreat to that city where he found that support for his cause was beginning to fall away; some of the eastern cities and some of the Roman governors had begun to switch their allegiance. The governor of Arabia, for example, was a native of Perinthus which Niger had attempted to capture. The decisive battle occurred at Issus, where Alexander the Great had defeated a Persian army more than five hundred years earlier. The Severan forces were helped by a thunderstorm which drove rain into the faces of Niger’s legions. Demoralised and retreating, they were ultimately caught in the rear by Severan cavalry which scattered the eastern legions and caught them on the run. The writer Dio claims that Niger’s forces lost 20,000 men in the battle. Niger himself was cornered and beheaded. The rest of 194 was taken up with settling debts, punishing the supporters of Niger and putting his own men in command of the eastern provinces and their legions.

In the spring of 195 Severus launched an attack into northern Mesopotamia, across the Euphrates river in order to punish the Parthian kingdom for its support of Niger. Surviving forces of the defeated Pescennius Niger had fled eastwards and found sanctuary within Parthian territory. Parthia had to be punished; that was the official line. The writer Dio claims that the entire expedition was conceived ‘out of a desire for glory’. Parthia was ‘the East’ and will dominate the narrative of this book. Emperors and generals like Crassus, Trajan and Mark Anthony campaigned in the east to secure glory and stature in the eyes of both Rome and of their own soldiers; Severus was no different. After a bloody civil war he may have wanted to give his troops (both western and defeated eastern) the opportunity to fight side by side, earn some victories and gain some plunder. It was during this period that two new legions, I Parthica and III Parthica, were brought up to strength, probably from the recruits hastily assembled by Niger in the east during his preparations. They would be trained and led by a core of veterans released from the Danubian legions.

During 195 his legions fought at least three major battles against Arab and Adiabeni forces. In response the senate began arrangements back in Rome to construct a triumphal arch for the emperor. While on campaign Severus took the bold step of naming Antoninus, his seven year-old son, ‘Caesar’ – that is, junior co-ruler and heir to the throne. This was a direct challenge to Clodius Albinus in Britain who was now cut out of the succession. Severus decided the time was right to move on his western rival and he began the march back to Rome.

During 196 Clodius Albinus crossed the Channel to Gaul with his own legions (around 40,000 men in total) and began his push to Italy. When he found the Alpine passes blocked he based himself at Lugdunum and began to raise additional forces there. On 19 February 197 the armies of Albinus and Severus met in battle on the outskirts of the city. It was no foregone conclusion, the size of the opposing armies was surprisingly well matched and Severus at one point was thrown off his horse; to avoid being identified and killed he tore off his purple cloak that would identify him as emperor. The arrival of Severan cavalry saved the situation and the battle swung against Albinus. Fleeing inside Lugdunum with some of his troops to escape the enemy, Albinus was forced to commit suicide. In an act of cruel pleasure Severus had his rival’s head cut off and sent to Rome before laying out the naked body and riding his horse over it. As an end to the matter the bodies of Clodius Albinus, his wife and his sons were thrown into the river Rhône.

Septimius Severus was now emperor without rival, with an heir designate and an army that had known nothing but victory. For this restless commander the rest of 197 was taken up with organising his unified empire, rooting out the supporters of Albinus from a number of provinces and marching once more to the east. In a determined attack on the Parthian kingdom, the Roman forces were able to capture and sack its capital, Ctesiphon. The emperor spent five years organising his two new provinces (Osrhoene and Mesopotamia) and touring Judaea and Egypt. He returned to Rome in 202.

The Changes

The military changes that would mark Severus’ reign and stand as a legacy throughout the third century began almost immediately. First – the Praetorian Guard. This force of around 8,000 soldiers provided a security force within Rome and provided a vital function, acting as bodyguard to the royal family and as a personal fighting unit on the battlefield. Traditionally open only to men of Italian birth, the Guard was quickly filled by Severus with deserving soldiers who had served in the northern legions. After this point Italians would no longer serve as Praetorians, more than half would come from western legions, the rest were recruited from units in the east. Most of those western legionaries would be Dalmatians and Pannonians. In a stroke Severus had removed a worrying threat and replaced it with a die-hard regiment of loyalist troops who loomed menacingly over Rome in his absence. The Guard still retained its power, however, and its elite membership were still keenly aware of this.

Severus initiated other changes. Three new legions, Legio I, II and III Parthica were established. Recruitment for Legio II Parthica probably began immediately in 193. It was partly raised through conscription of Italian natives, a process called the dilectus, which attracted recruits with the prospect of good pay and the chance of promotion. This was unusual, few Italians marched with the legions anymore. New recruits were more commonly found within the province that a legion garrisoned, and, more often than not, these provinces were out on the frontier. With Legio II Severus smashed tradition and based the new regiment at Albanum barely 34 km from Rome. Up until this point no imperial legion had been allowed a base within Italy in order to prevent it threatening Rome. Troop numbers for Legio I and III Parthica seem to have been raised in the east sometime during the following year. Officers and centurions for these three new legions would need to have some experience and almost certainly came from the Danubian legions that had marched to Rome with their emperor. Not only did this provide a core of military experience at the heart of each new legion, but it also ensured a level of personal loyalty to the emperor from soldiers who had elevated him to that position.

Contemporary writers were greatly concerned by the close proximity of Legio II Parthica to the capital, it represented the abandonment of a long-standing tradition that Romans considered important. At a distance of 34 km (23 Roman miles) it could easily be argued that the legion was positioned to intervene in Rome’s affairs at any time. Writing on military matters in the fourth century AD, Vegetius advises that Roman soldiers should be trained to march 24 Roman miles in five hours, ‘at the full step’, putting Legio II within five hours march of the capital. Was this an act of intimidation or one of defence? Opinion is divided.

Of more personal interest to the soldiers themselves, Severus gave his troops the right to marry. They had previously been able to have relationships with local women, unrecognized in law, and some maintained these partnerships through many years and several postings. Children were born within these relationships, but all were illegitimate. Marriage provided the wife with the legal right to her late husband’s estate and it legitimised his offspring. Such a move would have been good for morale and bolstered the opinion of Severus amongst his troops.

The grant to marry while in service was not the only popular appeal to the soldiery. For the first time since emperor Domitian (AD 81–96) Severus raised the annual pay of the legionary from 300 to 450 denarii. Likewise the auxiliary soldier saw his pay climb from 100 to 150 denarii. Legionary cavalry pay rose from 400 to 600 denarii, auxiliary cavalry pay rose from around 200 to around 300 denarii if part of a cohort, or from 333 to 500 denarii if part of a cavalry wing. Severus’ son Caracalla later followed suit after his father’s death, increasing pay so that it was double the value it had been during Commodus’ reign. Any increase was overdue; inflation had left the soldiers’ pay standing and increased the chance of the troops rallying to any leader who promised a donative (a one-off gift of money) should they fight for him in any civil war. Yet these large increases in pay cost the imperial treasury dearly, resulting in a debasement of the coinage.

Although these reforms resembled gifts bestowed on the legions by a grateful emperor, they did not destabilise the relationship between army and state. Far more damage was done by the favour now shown to frontier troops. Recruited from frontier provinces to maintain the manpower of legions stationed there, new recruits were often effective fighters. However, they lacked the crucial understanding any Italian would have, that a soldier of Rome owes absolute loyalty to the remote SPQR, the ‘Senate and the People of Rome’ and of course, to the man at the head of it all, the emperor. Legions manned by frontier recruits had a different loyalty, to that general who would give them donatives or chances for war and plunder.

At the command level, loyalties were also being tested to breaking point. Many centurions serving within the legions had been promoted from the ranks of the Praetorian Guard in Rome. Most would be Italians, with a strong sense of allegiance to the emperor, to Rome and to its institutions. Now that provincials from Britain, the Rhine and Danube were dominating the barrack blocks of the Guard, promotion to the centurianate of a legion no longer carried with it that traditional allegiance.

Command of the legion was the responsibility of a senator. As a legionary legate, this would mark another rung on the senator’s career ladder. Of course the senate embodied Rome, Roman values and Roman thinking – yet from the reign of Severus the number of senators receiving command positions began to drop until, by the reign of emperor Gallienus in 261, they were forbidden by statute to serve as legates at all. Instead the position was gradually opened up to the equestrians, a large ambitious class of wealthy families who were normally excluded from the privileges and responsibilities of government.

In all, Septimius Severus had aggrandised the legions, he was practising his own advice: ‘give money to the soldiers, and scorn all other men.’ Empowering the soldiers, in effect buying their loyalty with cash, promises and privileges, was crucial for the winner in a civil war, for if Severus could unseat an usurper so another chancer might just as easily march on Rome and do the same … unless the rules were changed. Severus was changing the rules, closing the door to potential rivals. That was probably his intent at any rate but in doing this he was handing over the keys of the empire to the miles, the common soldier.

Once Severus and his close kin were out of the picture the legions would not owe the new emperor any loyalties whatsoever. The seeds of disaster were sown.

Eboracum in AD 400

AD 400. The Legio Praesidiensis was in Eboracum [York], but the legionary fortress was straining to hold so many infantry and cavalry units at one time. The Duke of the Britains, who had his headquarters within the fortress, decided to billet the men of the Praesidiensis out amongst the population of the town, a common practice amongst the elite comitatenses field armies. Talk was rife that the build-up at Eboracum heralded the formation of a new and improved British field army to replace the one shipped across to Gaul in AD 398. That meant greater prestige, better pay, more chance of promotion and, most importantly of all, more reliable supplies.

York, with its crucial river-crossing in the heart of enemy territory, had been founded by the Roman military eager to subdue the local tribes. The legionary fortress was established in AD 71 on the northern bank of the River Ouse. It was soon accompanied by a civilian settlement to the south-west, immediately between the fortress and the river. The town also spread across the River Ouse and this southern section was linked to the fort by the all-important bridge. By the early third century, the settlement had been granted the status of colonia by the Emperor. This was an important legal distinction that enabled the city to govern itself through a senate (curia) of local aristocrats (decurions) elected to office. A century later York was a thriving and cosmopolitan city of perhaps 3,000 inhabitants (contrast that to Roman London’s 10,000) with its own city walls (probably built-in stone), its own forum, temples, wharves and warehouses, smart town-houses with mosaic floors and under-floor heating, shops, public baths, and street fountains – all laid out to a neat, rectangular plan. York had become the impressive second city of the British provinces, and one of the four provincial capitals.

In AD 400 the fortress was still occupied and maintained, although there was now some industrial activity occurring within the walls. The local garrison, the Sixth Legion, was significantly reduced in numbers but the fort continued to operate in a military capacity (plate 43). The civilian settlements north of the river around the fortress seem to have been abandoned by the late fourth century, yet the colonia south of the River Ouse continued in existence through to the end of Roman rule in the early fifth century. Perhaps the locals immediately outside the fortress sought shelter within the walls during the barbarian crises of the 360s and then remained there. The colonia had its own stone wall defences.

Other changes had occurred. The main road leading from the south, across the bridge and into the fortress had been narrowed during the fourth century. Timber booths or stalls had been erected on either side, perhaps to catch passing trade with food or other saleable items. Large and impressive houses had been built in various locations throughout the city during the early part of the century, and these houses, with mosaic floors, hypocausts and courtyards were probably the smart residences of administrators, wealthy merchants and retired military officers.

Archaeologists have identified several building remains that have been overlain with deposits that have become known as ‘dark earth’. A stone building on Wellington Row as well as a house excavated at Bishophill Senior and at 5 Rougier Street were overlain with this dark, silty deposit made up of decayed plant material mixed with domestic refuse, often finely broken up. Layers of this ‘dark earth’ have been discovered at other Roman town sites in Britain, and they seem to have become more common after the departure of the Romans in AD 410. There is no consensus of opinion as to what ‘dark earth’ actually represents. To some, the deposits are evidence of decay and abandonment, of roofless buildings overgrowing with vegetation and used as refuse pits by locals who can no longer rely on the struggling urban authorities to remove their waste. To others, the dark earth represents a new phase of timber dwellings with thatched roofs that spring up within the cities – signs not of decay but of a post-Roman survival.86 For others still, the earth is brought in from the fields to either support urban agriculture or to beautify the fortified area of the city with prestigious gardens.

The trend in Romano-British towns is for falling population levels and declining local economies. Some of the urban buildings uncovered by archaeologists in towns like Verulamium (modern St Albans) were obviously neglected and ruinous, some public areas were clogged with rubble or refuse. Buildings destroyed by fire during the late fourth century seem never to have been rebuilt, wooden lean-tos and huts were constructed either within or against empty town houses, and mosaics that formed the centre-piece of a Roman dining room have been covered over with gravel floors or scorched by the cooking fires of later tenants. Domestic rubbish has been found piled up in adjacent rooms.

The city was an invention imposed upon the British people by the Roman state shortly after the invasion of AD 43. More used to living in scattered farmsteads and upon fortified hill-forts, the British were induced to live within the newly established urban areas. For Rome the cities acted as administrative centres for the gathering of taxes and as economic powerhouses for the maintenance and feeding of the legions. In the time-honoured tradition, local aristocrats were encouraged to sponsor the construction and maintenance of public buildings. Rome did not fund the growth of cities directly; this was a local provincial concern. There was certainly no free-market economy fuelling construction by demand. In the third and fourth centuries the financial pressures on the landed gentry became intolerable, and many fled the cities for their villas in the country. Here they could lavish their fortunes on extensions and wall paintings, hypocausts and mosaic floors. The cities began their inevitable decline once the aristocracy had turned their energies, and their wealth, toward the country estates.

Eboracum had changed since Gaius had been there last. He had been forced to close his cowhide import business in AD 394 which had necessitated a trip to the city in that year. Many buildings had been boarded up, although many thought it a temporary measure. Some of the houses that had been neglected a long while had been torn down. Gaius remembered seeing a gang of workmen pulling down a wall with chains and iron hooks. A bystander told him the gang were artisans that had once toured the province installing mosaics in all the great villas. That was 394, when the sewers had still worked and the streets had still been clean. Now no-one paid for the necessities. In AD 400, less than six years later, Gaius was shocked at the difference. The streets had taken over from the choked sewers, filth ran freely down toward the river. There were large piles of animal dung at every crossroads. Many of the wooden boards had come off the abandoned town houses. Where the roof had collapsed the rooms had become rubble-strewn and weed-infested refuse piles. Plenty of high-class buildings were now home to the less well-off inhabitants of Eboracum: petty traders, criminals, labourers, prostitutes, refugees from the countryside, and out-of-work artisans. All were eager to live rent-free and close to the main thoroughfares.

Threading his way down a street choked with wooden houses and lean-tos, Gaius gazed on poor craftsmen and petty artisans desperate for work and unable to afford the customary rents. He suddenly spotted Claudius, the owner of the grand villa at Red Stone that he and his men had turfed out and bought off. The rich man and his family were now lowly refugees, buying food at high prices, without land, wealth or skills to sustain them. The timbers used to build this street of shanty-houses came from the roofs of the buildings on either side. The Sixth Legion had been through here last year and stripped off all the roof tiles as soon as regular deliveries of fresh tiles stopped arriving. Now flooded and useless for habitation, the town houses at least afforded good timber for the shanty huts

To ease the cramped conditions within the fortress, the Dux Britanniarum had ordered that the troops from Praesidium be billeted with local families. Gaius and Modesta followed the legionary clerk to their new billet; it was the river-side house of a wagon-driver and his family. Looking over the cramped conditions, Gaius turned back to the street. Within the hour, he and Modesta, Flavius and their two slaves were making the best of things in a townhouse. Recently abandoned and boarded up, Gaius had kicked in some of the hoardings and lit a cooking fire on the floor. The family members now had four rooms between them!

From summer AD 400 through to autumn AD 401, Gaius and his family lived reasonably comfortably within the town house. Flavius was now nine years old and helped his father re-establish his butchery business in Eboracum. The family still received army pay (although a great deal was still owed to them) and some of this helped to pay rent on a shop front along the main street. The business helped them survive their year in Eboracum, a strange year where Gaius spent more time at the butcher’s chopping block than the fortress fencing post. Customers always asked Gaius’ how he had lost his two missing fingers, but he never told the same story twice!

When his presence at the fortress headquarters was suddenly ordered, Gaius feared that he had unwittingly broken some military law. In his smartest tunic and cloak he stood waiting in the echoing hall, over 20m across and almost 70m long. Eight huge columns stood on either side of the hall, and light filtered in from glass windows high above. This was the largest building Gaius would ever stand in. While he leaned easily on a fat column base, legionary officials and soldiers on business hurried about looking anxious and over-worked. To his horror, Gaius was then led into the private chamber of the Dux Britanniarum, Caelius, Old Coel Hen, the Duke of the Britains who commanded the military forces of northern Britain. The duke was a bald-headed man, dressed in sumptuous white linen, embroidered with gold and silver. He wore a purple Pannonian hat and sat with his advisors at a desk covered with scrolls and wax tablets. The wall behind the duke was beautifully painted; one colourful panel depicted a columned shrine topped by a grimacing actor’s mask.

The meeting was short and direct. It had come to the duke’s notice that a centenarius once attached to his staff was now serving as a common foot-soldier in Gaius’ contubernium. This Justinus, a loyal man, no matter what the previous emperor had to say, was to be re-instated as a centenarius and given command of a cohort within the Legio Praesidiensis. Gaius was given credit by the duke for treating the disgraced officer fairly and without bitterness.

Despite the number of advisors in the room, and the maps and plans that littered the desks, there was no hint of the immense changes about to take place. A re-deployment was about to change the lives of every soldier in Eboracum, yet the Dux Britanniarum himself had no knowledge of it. Momentous events were taking place over in the Alps…

The Persian Onslaught I


‘As for you wretched Syria, I weep for you with great pity. To you too will come a fearful attack by bow-shooting men, which you never expected to befall you. The fugitive of Rome will come, brandishing a great spear, crossing the Euphrates with many thousands, who will put you to the torch and maltreat everything….Having despoiled you and stripped you of everything, he will leave you roofless and uninhabited. Suddenly anyone who sees you will weep for you.’

The Thirteenth Sibylline Oracle (c. AD 253)

In 253 Roman forces had marched against one another in order to defend their choice of emperor. Valerian and his son, Gallienus, had been the victors in that relatively bloodless showdown, north of Rome. Bloodless it may have been, but Valerian had marched into Italy at the head of an army that he had been ordered to raise for a campaign on the upper Danube. Valerian had been given that job by emperor Trebonianus Gallus and once news of Gallus’ assassination reached Valerian, he had decided to move the Danube legions into Italy – he planned to take the throne away from the usurper, Aemilianus.

This crisis of succession and of legitimacy in 253 obscured the real danger. Not only had the Danube frontier been weakened by the removal of its troops to support Valerian’s claim on Rome, but in the east the ruin and destruction wrought by the energetic Shapur, ruler of Sassanid Persia, still smouldered.

Shapur Takes the East

The wicked Shapur of whom I have spoken succeeded him (Ardashir) and lived on for thirty-one years more, doing great harm to the Romans

Agathias 4.24

Valerian was not a young man, he was already fifty-eight when he took the throne and his son, Gallienus, was forty. In a way this provided the new emperor with a nominated successor and a loyal co-emperor from day one of his reign. This situation might have been able to provide the stability that the empire desperately needed, but Fate would cruelly intervene. Leaving his son to organise the defence of the west, the emperor set out immediately for Syria in order to restore the situation there. He would never return.

Antioch was the second city of the Roman Empire and the shock of its fall and destruction resonates in the writings from the time. Although Roman forces had been soundly beaten at the battle of Barbalissos in 252 and much of Syria then occupied and plundered by Persian raiding forces, it seems that its jewel, Antioch, fell to King Shapur a year later. The city was offered to the Persians by the traitor, Myriades. This man had been a wealthy senator who had been expelled from the city for embezzling funds that were destined for the chariot races. In revenge Myriades offered his services to Shapur and led the troops directly to the gates. The rich fled from Antioch at the approach of the Persians, leaving behind the restless masses who seemed to be quite content with a change of government.

Shapur had ordered a huge battering ram to be fashioned, its head was indeed in the shape of a ram and solidly made of iron. It was massive, and once it had served its purpose was dragged to the city of Carrhae and abandoned. A hundred years later this same ‘antique’ ram would be dragged to the city of Bezabde by the legions in order to dislodge the Persians from that city. The fall of Antioch must have been sudden and unexpected, Eunapius writes how a comic actor on stage within the city suddenly declared to his audience, ‘Am I dreaming or are the Persians here?’ His audience fled in terror as missiles rained down upon them, the houses and temples were plundered, inhabitants killed or taken into captivity and the city set on fire. The treacherous Myriades, history records, was executed by Shapur once the city had been captured.

Valerian mustered his Roman forces and fought the Persian garrisons left behind by Shapur. It must have seemed to the emperor that he was making light work of the Persian occupation and raiding troops, but the King of Kings was holding his elite cavalry forces in reserve further east. An unnamed Roman victory in 257 was even substantial enough to be commemorated on an issue of coins bearing Valerian’s name.

When Valerian discovered that Shapur was besieging Edessa with great difficulty in 260, he launched a military expedition to fight the Persians there. However, the plains around Edessa and Carrhae were much suited to Persian cavalry and in addition the Roman troops were far outnumbered. Not only that but the equites Mauri (the Moorish cavalry) were stricken with the plague. Suffering a terrible defeat in June of that year and forced to retreat behind the walls of Edessa, Valerian had run out of options. Persian inscriptions claim that the Roman force had numbered 70,000 and that a great number were captured and deported to Iran. The emperor decided to attempt negotiation, it was perhaps the only option left to him. Shapur insisted he leave Edessa to talk, accompanied only by a small retinue of advisors and officers. Upon receiving the Roman delegation, the ‘wicked and bloodthirsty’ king captured them all. Valerian, the emperor of Rome, as well as high ranking Roman senators, the praetorian prefect and many others, were all enslaved. No emperor had ever been captured by the enemy before; the news stunned Rome.

Free now to roam at will, Shapur attacked Syrian cities in a renewed military campaign, sacking Seleucia, Iconium, Nicopolis, Tyana and, once again, Antioch. The Persian army even reached Cappadocia. The Roman forces, smashed outside Edessa, were little match for the Persian army. There was some spirited resistance in Cilicia where a Roman general named Ballista rallied Roman stragglers and made attacks on the Persians, now divided into smaller, more mobile raiding parties. He was able to capture the harem of Shapur along with a great deal of booty and his troops were able to wipe out a force of three thousand Persians.

Shapur, realising he had outstayed his welcome, turned his forces east and headed for home. He first had to bribe the fierce citizens of Edessa in order that he might pass unmolested. Odaenathus, king of Palmyra, a wealthy caravan city allied with Rome, could not be bribed – and he harried the retreating Persians along the Euphrates river frontier. Thousands of prisoners were marched east by the Persians, fed on the bare minimum to support life and allowed to drink once a day, being driven to water by their guards like cattle. According to the writer Zonaras, at one point the retreating column reached a gorge impassable to Shapur’s baggage animals. The king ‘ordered the prisoners to be killed and thrown into the gorge so that when its depth was filled up with the bodies of the corpses, his baggage animals might make their way across.’

Of course Valerian was now also a prisoner. Accounts differ about how long he survived; Aurelius Victor claims that he was quickly hacked to death, but others insist the emperor lived out his life in servitude to Shapur. As a common slave, Valerian, a man in his sixties, was humiliated and forced to stoop and allow Shapur to step on his back to mount his horse. Lactantius claims that when Valerian eventually died, the Persian king had his body skinned. The old man’s skin was dyed with vermillion and then stretched upon a wall so that future ambassadors from Rome might look upon poor Valerian evermore as a symbol of Rome’s military vulnerability.

Had Valerian left no heir it is likely that a new round of civil wars would have torn through the empire. However, Valerian had entrusted the western half of the empire to Gallienus, his capable son and co-emperor. But if Romans had thought that the future could not get any worse, they were sorely mistaken.

The Era of Pretenders

Now let us pass on to the twenty pretenders, who arose in the time of Gallienus because of contempt for the evil prince.

Historian Augusta, Life of Gallienus 21

While Valerian spent his final years of freedom in the east waging war against the Persian army, his son Gallienus was no less busy on the northern frontier. German tribes beyond the Danube river were beaten back during the years 254 to 256, and once that frontier was secure, the focus shifted to the defence of the Rhine. Attacks came thick and fast. Although Gallienus claimed the title of ‘Germanicus Maximus’ for himself five times and issued coins celebrating his victories beyond the Rhine, he was soon back on the Danube (258). Yet, despite his furious fire-fighting Gallienus could not be everywhere at once and further west the Juthungi broke through the military frontier (limes).

From the North Sea, the river Rhine snaked southwards to provide a natural barrier against the German tribes to the east. Meanwhile, Italy, Pannonia and Thrace received the protection of the river Danube which ran from southern Germany eastwards to the Black Sea. North of this frontier, German and Sarmatian tribes squared off against the local Roman garrisons. However, these ‘wet’ frontiers, formidable natural moats that took great effort to breach, did not meet. This vulnerable gap at the headwaters of the Danube and the Rhine was kept free of German invaders with only a man-made defensive line. The modern-day German state of Baden-Württemberg represents the vulnerable provincial settlement known as the Agri Decumates that lay behind this frontier.

For the previous twenty years attacks had been frequent and punishing on this defensive weak point. At Castra Vetoniana (modern Pfünz) excavations seem to suggest that the soldiers of cohors I Breucorum had been so surprised in one attack that gate guards had no time to grab their shields. Repeated Germanic attacks eroded the military installations and their garrisons to a point that made the 259 invasion possible. The Juthungi descended on Italy and marched toward Rome where a hastily assembled army turned them back – they were defeated near Mediolanum (Milan) by the forces of Gallienus. The weakened sector of the frontier had exposed Italy to the ferocity of the northern tribes. Rome, a city without fortifications, had not felt this vulnerable since the first century BC.

Unsurprisingly, the Agri Decumates was hastily abandoned – that frontier was now considered untenable. Yet attacks continued relentlessly. The Alemanni invaded Italy in 260 while other raiders ravaged as far as Gaul and Spain. The northern borders were crumbling, as was confidence in the emperor Gallienus. Beleaguered provincials who were threatened with continued barbarian attacks, and some of the emperor’s own generals, had lost faith in Gallienus’ ability to defend the empire.

The Usurpers

The invasion of northern Italy and the abandonment of the Agri Decumates region, coupled with the Roman defeat at Edessa and capture of Valerian, triggered a wave of usurpers all eager to prove that they could do better. Although the Historia Augusta talks of twenty pretenders, there were in fact fewer serious contenders. First was Ingenuus, governor of Pannonia and Moesia, with plenty of legions at his command. He was defeated in battle at Mursa, northwest of modern Belgrade, by a Roman army led by one of Gallienus’ top generals called Aureolus. This seething frontier produced another discontented general, Regalianus, who was proclaimed emperor by the remnants of Ingenuus’ broken army in late 260. He was murdered by his own troops.

Syria had more right than most to be discontented and late in 260 the legions there threw their support behind Macrianus and Ballista, the two generals who had pulled together some kind of military response to the terrible Persian onslaught following Valerian’s capture. Macrianus was hailed as emperor by the eastern troops he commanded but being of advanced age and infirm, he passed that title to his two sons, known together as the Macriani. The two brothers were named Fulvius Iunius Macrianus and Fulvius Iunius Quietus. Proclaimed joint emperors and enjoying the support of the war-weary eastern provinces they planned to take control of the empire. Macrianus (the older of the two brothers) marched against Gallienus with an army numbering 45,000. Again the general Aureolus counter-attacked and in 261 his forces encircled the army of the rebels in Illyricum (the region of former Yugoslavia). The trapped legionaries suddenly switched sides and ended the rebellion.

Quietus, the younger of the Macriani, had remained in Syria with Ballista and both men had taken refuge within the city of Edessa. Here, Gallienus was able to call on Odaenathus, an ally in the east on whom he could depend. As the ruler of wealthy Palmyra, untouched by Persian aggression, Odaenathus commanded the premier fighting force on the eastern frontier. Following the earlier Palmyrene attacks on the Persian columns and the capture of Shapur’s harem, Gallienus had rewarded Odaenathus with the honorary title of dux Romanorum (‘regional commander’). Edessa was soon besieged by the Palmyrene prince who executed Quietus and Ballista once the city had fallen. He did this on behalf of Gallienus.

The eastern uprising had been quashed but plenty of bitterness and resentment circulated throughout the empire. Mussius Aemilianus was governor of Egypt and had been part of the Macriani revolt. Now he claimed the throne but like the Macriani, he was defeated in battle and executed early in 262.

Even Aureolus, the emperor’s trusted general, rebelled in 262 but he was forced to back down and make peace with his master. Unusually, the emperor let him retain not only his life but also his position and power. Perhaps he needed the military talent of Aureolus too much to have him executed.

Fragments of Empire

Upon the news of Valerian’s capture and enslavement, the governor of Lower Germany, Marcus Cassianus Latinus Postumus, rose in revolt against Gallienus. Postumus had ably dealt with a Germanic attack and on the strength of this victory, had his troops proclaim him emperor. In the autumn of 260 he marched to Colonia Agrippina (modern Cologne) where the young son of Gallienus, Salonius, had been installed as co-emperor with his father. Postumus refused to give up the siege of the city unless Salonius was handed over to him. Once the folk of Colonia Agrippina agreed to the demands, both the boy and his guardian were executed.

Unlike past usurpers who had usually gathered together a military force and then made a dash to Rome, Postumus seemed content to remain beyond the Alps. Using the Rhine legions, he was able to clear the western provinces of barbarians and in doing so he earned the loyalty of the British, Spanish and Gallic provinces. The governors and legionary commanders decided to recognise Postumus as the legitimate emperor over those territories. This was not a re-run of power-sharing between Clodius Albinus and Septimius Severus in 193, Postumus had, in a stroke, created an alternative Roman Empire, one based primarily upon the defence of the western provinces that was ruled from Augusta Treverorum (modern Trier). Postumus made it clear that he was satisfied with the western provinces and did not spoil for a fight, this was just as well, for Gallienus was struggling to cope with a series of usurpers from 260 to 262.

It was not until the spring of 265 that Gallienus felt confident enough to challenge Postumus and marched a Roman army deep into Gaul. An early victory led to the bottling up of Postumus within a city (possibly Lugdunum, modern Lyons) followed by a siege. While the emperor inspected the siege works constructed by his troops, a defender shot Gallienus in the back with an arrow, seriously wounding him. He was evacuated back to Rome in order to recover and although Aureolus was left in charge of the conflict he seems to have made some kind of deal with Postumus, lifting the siege and letting the usurper escape. The Gallic Empire was thereafter left unmolested by Gallienus who continued to face the inevitable distractions – the renewed invasions that would continue to batter what was left of the Roman Empire.

This break-away Gallic Empire survived as an independent state for the next fourteen years; it was made up of the three provinces of Gaul (Aquitania, Narbonensis and Lugdunensis), the two German provinces (Upper and Lower), the three Spanish provinces (Tarraconensis, Lusitania and Baetica), Raetia and the two British provinces (Superior and Inferior). Raetia was taken back by Gallienus in 263 and the Spanish provinces, along with eastern Narbonensis (that area east of the Rhône) were all recovered in 269. However, a measure of the Gallic Empire’s success can be gleaned not just from its relative longevity but also from the fact that all of its four emperors refused to march on Rome and they instead focused on protecting the territory from incursions beyond the Rhine. The third century ‘disease’, that of imperial succession by military assassination plagued the successors of Postumus just as it did Rome; all but the last of the Gallic emperors were murdered.

In a sense, the Gallic Empire depicts the Roman Empire cracking and disintegrating under pressure, and as events in Syria would soon show, it was not just the west that wanted to go its own way. The mass eastern support of the Macriani in 260 indicated a similar provincial sentiment – that of a desire for firm local control in the face of a foreign onslaught. In 270 the east would officially break away from Rome which effectively created three separate imperial powers.

In 266, as the emperor Gallienus recovered from his arrow wound, Odaenathus, the ruler of Palmyra, spearheaded his own military campaign against Persia. Driving deep into Mesopotamia he was able to win a stunning victory at Ctesiphon, the Persian capital, an achievement matched only by three Roman emperors before him. These men had the weight of Rome’s military behind them; Odaenathus had his elite Palmyrene cavalry backed by the military forces of the eastern provinces. It was clear that this potentate was running the show in Syria and Mesopotamia.

From the viewpoint of Gallienus, looking outwards from Rome, the Gallic Empire in the west was dealing effectively with German raids. In the east, the Roman proxy Odeanathus was thrashing the Persians on their own territory. Meanwhile, the Danube frontier was quiet. Did this mean peace for Rome at last?