Roman Dromedarii. Dromedarii are auxilliary troops recruited in the desert provinces of the Eastern Empire to take the place of light cavalry in scorching desert conditions.
As light troops these men are most useful as screening and scouting forces, although they can be surprisingly effective against other cavalry especially when the enemy horses are unused to the repulsive (to horses) smell of camels. Recruited from among the local desert tribesmen, dromedarii are peculiar to the Eastern Roman Empire and a specific answer to the problem of fielding light cavalry along the frontier.
Over time, the Romans expanded the borders of their African province. Colonization was encouraged, and the region enjoyed four centuries of prosperity.
For more than a century from its acquisition in 146 bce , the small Roman province of Africa (roughly corresponding to modern Tunisia) was governed from Utica by a minor Roman official, but changes were made by the emperor Augustus, reflecting the growing importance of the area. The governor was thenceforward a proconsul residing at Carthage, after it was refounded by Augustus as a Roman colony, and he was responsible for the whole territory from the Ampsaga River in the west to the border of Cyrenaica. The proconsul also commanded the army of Africa and was one of the few provincial governors in command of an army and yet formally responsible to the Senate rather than to the emperor. This anomaly was removed in 39 ce when Caligula entrusted the army to a legatus Augusti of praetorian rank. Although the province was not formally divided until 196, the army commander was de facto in charge of the area later known as the province of Numidia and also of the military area in southern Tunisia and along the Libyan Desert. The proconsulship was normally held for only one year; like the proconsulship of Asia, it was reserved for former consuls and ranked high in the administrative hierarchy. In the 1st century ce it was held by several men who subsequently became emperor-e. g., Galba and Vespasian. The commanders of the army normally held the post for two or three years, and in the 1st and 2nd centuries it was an important stage in the career of a number of successful generals. The two Mauretanian provinces were governed by men of equestrian rank who also commanded the substantial numbers of auxiliary troops in their areas. In times of emergency the two provinces were often united under a single authority.
Tribes on the fringe of the desert and beyond constituted more of a nuisance than a threat as the area of urban and semiurban settlement gradually approached the limit of cultivable land. A number of minor conflicts with nomadic tribes are recorded in the 1st century, the most serious of which was the revolt of Tacfarinas in southern Tunisia, suppressed in 23 ce. As the area of settlement extended westward as well as to the south, so the headquarters of the legion moved also: from Ammaedara (Haidra, Tun.) to Theveste under Vespasian, thence to Lambaesis (Tazoult-Lambese, Alg.) under Trajan. Tribal lands were reduced and delimited, which compelled the adoption of sedentary life, and the tribes were placed under the supervision of Roman “prefects.” A southern frontier was finally achieved under Trajan with the encirclement of the Aures and Nemencha mountains and the creation of a line of forts from Vescera (Biskra, Alg.) to Ad Majores (Besseriani, Tun.). The mountains were penetrated during the next generation but were never developed or Romanized. During the 2nd century stretches of continuous wall and ditch – the fossatum Africae – in some areas provided further control over movement and also marked the division between the settled and nomadic ways of life. To the southwest of the Aures a fortified zone completed the frontier defensive system, or limes, which extended for a while as far as Castellum Dimmidi (Messad), the most southerly fort in Roman Algeria yet identified. South of Leptis Magna in Libya, forts on the trans- Saharan route ultimately reached as far as Cydamus (Ghadamis).
In the Mauretanias the problem was more difficult because of the rugged nature of the country and the distances involved. The encirclement of mountainous areas, a policy followed in the Aures, was again pursued in the Kabylia ranges and the Ouarsenis (in what is now northern Algeria). The area round Sitifis (Setif) was successfully settled and developed in the 2nd century, but farther west the impact of Rome was for long limited to coastal towns and the main military roads. The most important of these roads ran from Zarai (Zraia) to Auzia (Sour el-Ghozlane) and then to the valley of the Chelif River. Subsequently the frontier ran south of the Ouarsenis as far as Pomaria (Tlemcen). West of this area it is doubtful whether a permanent road connected the two Mauretanias, sea communication being the rule. In Tingitana, Roman control extended as far as a line roughly from Meknes to Rabat, Mor., including Volubilis. Evidence attests to periodic discussions between Roman governors and local chieftains outside Roman control, suggesting peaceful relations. However, the tribes of the Rif Mountains must have lived in virtual independence, and they were probably responsible for a number of wars recorded in Mauretania under Domitian, Trajan, Antonius Pius (which lasted six years), and others in the 3rd century. They did little or no damage to the urbanized areas and never necessitated a permanent increase in the African garrison. The defense of the North African provinces was far less a problem than that of those on the northern periphery of the empire. For Numidia and the military district in the south of Tunisia and Libya, about 13,000 men sufficed; the Mauretanias had auxiliary units only, totaling some 15,000. This may be contrasted with the position in Britain, where three legions and auxiliaries (all told, some 50,000 men) were required. From the mid-2nd century ce the African garrison was largely recruited locally.