Roman Emperor Marcus Aurelius [Marcus Aurelius Antoninus Augustus; 26 April 121 – 17 March 180] believed that the barbarian groups beyond the Rhine and the Danube had been allowed too much freedom of action while three of the regional legions had been fighting in the east. Indeed, both archaeological evidence and the scant literary sources suggest that the balance of tribal power beyond the middle Danube and in Bohemia had changed dramatically around this time, though for reasons that remain obscure. Relative imperial neglect probably played a part, allowing unexpected and undesirable violence to break out. Authorised warfare between tribal clients was a healthy part of Roman policy as it created a managed instability that prevented any one group from becoming too powerful and channelled the excess energy of martial societies away from Rome and towards one another. But unauthorised warfare beyond the northern frontier was something different: without sufficient Roman oversight or surveillance, it might rapidly flare up into something more threatening. Defeated war bands, occasionally whole tribes, might try to seek refuge in the empire, and while that was often a desirable way of bringing new farmers and soldiers into the empire, it only worked when such population movements could be controlled.
Nowadays Rome’s European frontiers, with their ‘Germanic’ barbarians, loom disproportionately large in the historical imagination, both popular and scholarly: the frontier is often imagined as a breakwater against which barbarian tides lapped endlessly across centuries until the dam burst and the empire fell. In fact, the political dynamics on the Rhine and Danube frontiers were similar to those in Africa, Arabia, Britain and wherever the socially more complex and technologically more sophisticated empire confronted tribal groups whose power structures rarely stayed stable for long. For those neighbours, the empire was a juggernaut towering on the horizon. Roman actions, and fear of Roman actions, shaped the decisions of barbarian elites everywhere, even those at three or four removes from the frontier itself. The churning landscape just beyond the European and African frontiers was as much a product of Rome as the barbarians: even the smallest Roman expedition could wipe out whole sections of a population, lay waste to years’ worth of seed grain and stockpiled wealth and render a group’s homeland uninhabitable. When the empire was distracted, it presented an opportunity. Not to correct the immeasurable disparity in power, that could never happen; rather to seize momentarily a small piece of Roman prosperity, accessible along well-built roads leading deep into the imperial provinces. To do so was worth the inevitable and often devastating response. We have no idea what was happening beyond the Danube frontier when some of its garrison legions were detached to the Parthian War. But the return of the legions either directly provoked a violent response or triggered an outbreak of intertribal violence that drove a medium-sized barbarian army into Pannonia.
Marcus’s response was determinedly punitive. Iallius Bassus, who had been with Lucius on the eastern campaigns, was made governor of Pannonia Superior, traditionally the most senior command on the Rhine–Danube frontier. At the same time, a man named Tiberius Claudius Pompeianus first enters the historical record as the governor of Pannonia Inferior. Pompeianus is a remarkable example of the way in which the oligarchic elite that dominated imperial government could open itself to conspicuous talent. Pompeianus was the son of a minor equestrian official from Antioch in Syria, a part of the Hellenistic east that had as yet launched very few of its native sons into the international elite of equestrian, let alone senatorial, government. On his personal merits alone, however, Pompeianus would go on to enter the senate, becoming a special friend of Marcus, marrying into the imperial family and remaining a central figure in Roman politics for the rest of the century.
Pannonia Inferior was Pompeianus’s first significant command, and both he and Bassus would experience very heavy fighting. Late in 166 or early in 167, several thousand Langobardi and Obii invaded Pannonia Superior. They had come from a region well beyond the immediate frontier zone, which was settled with Marcomanni opposite Pannonia in the modern Czech Republic, Quadi opposite the Danube bend, and the Sarmatian Iazyges in the land between the Danube and the Carpathians. These distant invaders were rapidly annihilated by Bassus, but the prospect of reprisals frightened the client kings closer by. Eleven of the middle Danubian tribes chose as their spokesman the Marcomannic king Ballomarius and he sued for peace before Bassus. Ballomarius protested his own and his fellow clients’ loyalty to the emperor and dismissed the actions of the Langobardi and Obii as a freak aberration. The plague had detained Marcus at Rome, so Bassus concluded a provisional peace and waited until his emperor was ready.
In spring 168, Marcus began a personal inspection of the Danube frontier. No one doubted that this was a preamble to war. Lucius would accompany the expedition as well, in part because the troops knew him from the Parthian War, and the project’s scale can be judged by the number of important men involved. Furius Victorinus, the experienced guard prefect who had accompanied Lucius to the east, now went north with both emperors, but he and many of his guardsmen would die, probably of plague, en route to the frontier. He was replaced by M. Bassaeus Rufus, previously prefect of the vigiles (the urban security force of Rome) and briefly prefect of Egypt. The other guard prefect, M. Macrinius Vindex, came, too, which suggests that Rome was left ungarrisoned in the emperors’ absence. Marcus’s other trusted generals – Aufidius Victorinus, Dasumius Tullius Tuscus, Pontius Laelianus, the last two of whom had both served stints on the Danube frontier – were with him, not with specific portfolios but as comites Augusti, companions of the emperor.
Our sources are confused and two centuries of modern scholarship have yet to produce a fully satisfactory chronology of what we call the Marcomannic Wars and what Marcus referred to as his expeditio Germanica. The frontier of Pannonia Superior had not been settled by the treaty of Ballomarius and Bassus, and by 168 a Marcomannic king (perhaps, but not necessarily, Ballomarius) had been killed in battle there. The tribal leaders asked Roman permission to choose his successor and Lucius argued that this was success enough: why not call off the whole campaign and spare themselves the expense and the danger? Marcus demurred, planning to spend winter outside Rome for the first time since becoming emperor, choosing instead the Adriatic hub of Aquileia which was equidistant from the capital and the frontier. In the end, sickness in the ranks proved so bad that Marcus acceded to Lucius’s wishes and agreed to return to Rome. But having got his way, Lucius proved unlucky: just days after leaving Aquileia, he had a stroke and died at Altinum. Marcus returned to Rome with his adoptive brother’s body. He was now sole emperor, as Antoninus Pius had always intended.
There was little time for grief, but Marcus had his brother deified as duty required. Lucius’s death left Marcus’s 19-year-old daughter Lucilla the widow of a divus. She may already have begun to show the ambition and ruthlessness that would define her later career, or Marcus may have felt that a marriageable princess was too tempting a target for court intrigue. Regardless, he scandalised senatorial opinion by marrying Lucilla off again before the mourning period for Lucius was over. Worse still, she was given not to a senatorial grandee, but to the equestrian marshal Ti. Claudius Pompeianus. Marcus had good reasons for this decision. Only one of his daughters was ever given an aristocratic husband, lest it lead to a dynastic challenge to the heir apparent, Lucius Commodus (he became the emperor’s only surviving son after the youngest, Annius Verus, died in summer 169). Pompeianus proved a loyal supporter of the dynasty, as well as an important patron for other equestrians. Most significant of these was Helvius Pertinax, the equestrian son of a freedman, who was adlected into the senate without ever having set foot in the senate house, or serving in the qualifying posts of quaestor, aedile or praetor. That he would eventually become emperor, even if only briefly, illustrates some of the social change that was overtaking Roman society, not least under the combined pressure of plague and war and the indiscriminate death toll they took on the traditional elites.
The marriage of Lucilla to Pompeianus – which both she and her mother Faustina had vigorously opposed – was not the only scandal of 169. New legions had to be raised for the Marcommanic campaigns and, in order to finance them, Marcus auctioned off property from the imperial household. The event was proverbial in antiquity, and has become a handy shorthand for imperial crisis in the modern scholarship, but it was a gesture of neither ostentatious self-sacrifice nor personal frugality. It was, rather, the only way to generate fresh revenue without raising taxes at a time when a badly depleted population might not be able to pay them. Fresh soldiers were in such short supply that Marcus authorised the recruitment of gladiators into the legions, an unprecedented action which drove up the price of public games across the empire and fell so heavily on local magistrates that Marcus soon enacted price-capping measures.
These varied financial expedients were ultimately successful and by late 169 Marcus was ready to return to Pannonia. Faustina stayed in Rome with the young and sickly heir to the throne, Lucius Commodus. Pompeianus came with Marcus as his chief counsellor, which meant that Lucilla did, too, as did many veteran commanders of the eastern wars: Pontius Laelianus, Dasumius Tullius Tuscus, Claudius Fronto. Where they over-wintered is unclear, perhaps at either Singidunum or Sirmium (respectively Belgrade and Sremska Mitrovica in modern Serbia), both now coming to prominence as major imperial cities. Indeed, Marcus’s Danubian wars mark a transition in the history of the Balkan provinces, previously cultural backwaters but thereafter increasingly urbanised and studded with wealthy farms and villas that would make the region central to imperial history in the coming centuries: as our story continues, a much longer list of Balkan towns – Mursa, Naissus, Poetovio, Serdica, Viminacium, Nicopolis ad Istrum – will join Sirmium and Singidunum in these pages.
Marcus himself led the major offensive of 170, pushing deep into Marcomannic territory. It was a fiasco: imperial propaganda was capable of turning a trivial skirmish into a towering victory, but now there is not so much as a whiff of success in the sources. Instead, the campaign triggered a massive barbarian invasion of Italy. Aquileia was besieged and the North Italian plain penetrated. This was an early harbinger of later history – Italy had to be defended at the Alps or, better still, just beyond them. If Alpine defences failed, the peninsula was effectively ungarrisoned and helpless. In 170, the Balkans also experienced heavy damage. The Costoboci, a tribe whose name is otherwise barely known, made it all the way to the province of Achaea, indeed as far as Attica, where they violated the shrine of the Eleusinian mysteries. The invaders’ numbers, their divisions, their routes, all are unrecoverable, but they did more than ravage crops and kidnap farmers, which the government usually tolerated as an acceptable loss. Instead, there was a lot of hard fighting against Roman forces, with conspicuous and high-level deaths: in 170, the governor of Moesia Superior, whose name is not preserved, was either killed or cashiered for incompetence. His command was given to the governor of Dacia, the experienced Claudius Fronto, who himself fell in battle before the year was out. The emperor’s own army got cut off beyond the Danube, and a special fleet command, under Valerius Maximianus, was needed to carry supplies to Marcus and his troops.
Meanwhile, Claudius Pompeianus, with Helvius Pertinax as his chief lieutenant, began to clear northern Italy of its unwanted guests. Fighting at the frontier continued in 171, when Marcus was headquartered at Carnuntum near modern Vienna. A barbarian army that Pompeianus had chased out of Italy was now trapped at the Danube crossing and destroyed. Marcus divided the plunder he retrieved among the provincials, and these victories, though small, contained the damage well enough to allow a return to the traditional policy of setting one group of barbarians against another. That seemed to work. As the end of the campaigning season approached in autumn 171, Marcus received various embassies at Carnuntum. The Quadi made peace, offering to supply the Roman army and agreeing to prevent the passage of either the Marcomanni or the Iazyges (their western and eastern neighbours, respectively) through their territory. Other defeated barbarians were allowed into imperial territory and settled deep in the interior provinces. It was all starting to look like a return to frontier business as usual, welcome because there was now trouble elsewhere: the Mauri who had caused trouble under Antoninus Pius were again raiding across the straits of Gibraltar into Spain, which required an emergency arrangement combining the imperial province of Hispania Tarraconensis with the ungarrisoned senatorial province of Baetica under a single military commander.
In the next year, 172, the value of Marcus’s Quadic treaty became clear. With the middle Danube bend and the Dacian fronts calm, Marcus was able to launch a second invasion beyond the river, focused solely on the Marcomanni in what is now Bohemia. It was another arduous campaign, during which one of the praetorian prefects, Macrinius Vindex, was killed in battle. But Marcus had gained the confidence of his troops and they began to attribute to him a supernatural ability to call down aid from the gods. In one case, he was said to have summoned a thunderbolt to destroy a barbarian war engine, an event duly commemorated on coins; in another, he (or rather his favourite, the Egyptian magician Arnouphis) had apparently summoned a rainstorm to revive his parched and exhausted troops: they proceeded to win a victory against all odds. Both miracles are depicted on Marcus’s column in the Piazza Colonna at Rome, and coins seem to credit Mercury for the miraculous victory. The scale of actual military achievement may not have been equal to the propaganda triumphs, though both Marcus and the caesar Commodus had taken the victory title Germanicus before the start of 173. Commodus may have been at the front with his father, which would mean that most of the imperial family, including Faustina, Lucilla and her husband Pompeianus, were at Carnuntum late in 172. In the following year, Faustina was hailed as mater castrorum, mother of the camps, a sign that the soldiers regarded her as a protecting patron. Not long afterwards, the rest of the family also joined Marcus and Faustina on the Danube: Fadilla, now married to Lucius Verus’s nephew Plautius Quintillus; and Cornificia, married to Petronius Sura Mamertinus, grandson of Pius’s praetorian prefect Mamertinus. And then bad news came from the east.
In 172, while Marcus was proclaiming success on the Danube front, there was either a fully fledged uprising or an outbreak of intensive banditry in the Egyptian delta. At the same time, the Parthians attempted to bring Armenia back under the tutelage of Ctesiphon, no doubt emboldened by the detachment of some imperial troops from Cappadocia to the Danube. But the scale of the Danubian war meant Marcus could not give the east the attention it needed, and there was no longer a Lucius Verus available to serve as the face of the imperial dynasty. Avidius Cassius, the long-serving governor of Syria and a native Syrian himself, was granted extraordinary imperium in the east, of the kind that no one outside the imperial family had possessed since the days of Augustus’s trusted lieutenant Agrippa a century and a half before. In practical terms, Cassius had become Marcus’s plenipotentiary east of the Bosporus and the suppression of Lower Egypt was his first task.
Meanwhile, Marcus passed most of the campaigning season of 173 beyond the Danube, possibly reaching as far as the headwaters of the Vistula. The Quadi were certainly one target, perhaps because they had broken their oath not to help the Marcomanni. In the following year, he turned against the Iazyges beyond the Danube bend, in the Great Hungarian plain between the river and the Carpathians, or, in Roman terms, between Pannonia and Dacia. He did well enough to refuse the Iazyges the peace terms they sought, preferring to continue the fighting in 175. That year brought something far worse than another round of frontier warfare: Avidius Cassius, perhaps the most reliable man Marcus had, revolted and claimed the imperial title.
Marcus still expected to die soon, and he was unsettled by what he saw on the frontiers. The Mauri in Tingitania remained uncontrollable: a group had again crossed into Baetica to raid and had even laid siege to the town of Singilia Barba (modern Antequera in Málaga province). Meanwhile, the Danube was again calling and, though Marcus would take personal charge of the campaign, he wanted Commodus to gain the experience of real war. To shore up the dynasty before they set out, he married Commodus to Bruttia Crispina, the descendant of a leading Hadrianic aristocrat; her father, Bruttius Praesens, already a prominent man when he was made consul in 153, was designated as consul for the second time for 180. In August 178, the emperors left for the Danube front. Old Pompeianus went with them as always, and now Commodus’s father-in-law Bruttius did, too. Both guard prefects, Tarruttienus Paternus and Tigidius Perennis, accompanied the expedition and both would keep their posts into the next reign. Helvius Pertinax was made governor of Dacia, to support the flank of the main army, and Paternus was put in charge of the field army; the campaign proper was launched in 179 into Quadic territory at the Danube bend. Modern scholars are divided over whether Marcus intended to conquer and hold a new province of Marcomannia beyond the Danube, but the sources, written and archaeological, reveal dozens of Roman forts throughout what is now Slovakia and the Czech Republic, and it is certainly possible to discern in them a prelude to occupation and provincialisation.
At the start of the next year’s campaigning season, however, Marcus fell gravely ill yet again. It may be that he had finally succumbed to the plague, but he had never been particularly robust, so we cannot be sure. Nor are we sure quite where he was when this final sickness overtook him – perhaps near Sirmium. He summoned Commodus, commended him to the counsel of his own senior advisers and begged him to continue the war effort whether or not he was personally inclined to do so. The old emperor then proceeded to starve himself, perhaps hoping that this would cure his illness, perhaps trying to hasten death. After seven days, on 17 March 180, he knew he was dying. When the duty tribune asked him for the day’s watchword, which it was the emperor’s task to set, Marcus sent the man to Commodus: ‘Go to the rising sun,’ he said, ‘for I am now setting.’
Commodus’s first decision as sole emperor, so far as we can tell, was to conclude a treaty with the Marcomanni and the Quadi. This left intact the old line of the Danube frontier, scotching any plans Marcus might have had for imperial expansion, and it brought to the region a peace that endured for half a century. The terms were very much in Rome’s favour. The defeated tribes were required to supply the empire with an annual tribute of grain and to collectively contribute more than 20,000 soldiers to the Roman army. They would be posted to distant auxiliary units and kept away from their homeland to break down any lingering sense of tribal identity they might have. Back home, both the Marcomanni and the Quadi were partially disarmed and forbidden to attack their neighbours – the Iazyges, the Buri and the Vandals – without Roman permission. They were also forbidden to make use of the Danube islands and even of a strip of land on their own, left bank of the river. Large-scale political meetings could take place only when a Roman centurion was present to supervise.
In many ways, Commodus’s decision to end his father’s war was wise. It restored the old imperial preference for client kingships in regions not worth the effort of conquest and it made sure those clients would be dependent upon Rome for their hold on internal power. An unintended, but ultimately more lasting, consequence was the efflorescence of civilian life and Roman civil society in the Danubian provinces, which had developed very quickly thanks to two decades of wartime investment in the region’s infrastructure. Thus it is not true, as many have argued, that Marcus’s worthless son threw away the chance to create a great trans-Danubian province as his father had planned. There is no definitive evidence that Marcus was planning to extend the frontiers into central Europe, and the return to the pre-war status quo was both strategically sound and tactically sensible. What is more, however much Marcus’s trusted old adviser Claudius Pompeianus, brother-in-law to the new emperor, might argue against the return to Rome, Commodus would have to present himself to the people to be acclaimed by them and the senate. Delay would breed their resentment, while the military’s dynasticism would keep the frontiers quiet for a time. As soon as the treaty was concluded, Commodus presented himself at Rome as the son of the deified Marcus and the bringer of peace through conquest. He celebrated a formal triumph on 22 October 180.