At the beginning of Justinian’s reign in 527, the armies of the east Roman empire were organised into five mobile field armies and a large number of smaller regional divisions along and behind the frontier regions of the empire. The field army units were referred to as comitatenses, and were each commanded by a magister militum, or ‘Master of the Soldiers’. The five divisions were those of the east (a huge region including both the Armenian and Mesopotamian fronts with Persia, as well as the Egyptian desert front), Thrace, Illyricum, and two further corps ‘in the presence’ of the emperor (inpraesenti), based in north-west Asia Minor and in Thrace to defend Constantinople - in the days when emperors had personally commanded their field troops, these had been their divisions. By Justinian’s time this tradition of personal command had lapsed, although under Heraclius in the Persian war (622-629) it was revived. The troops making up the frontier divisions and permanent garrisons were known as limitanei, mostly composed of older legionary units and associated auxiliary units, backed up by mixed corps of auxiliary and legionary cavalry to provide local reserves.
Justinian undertook several reforms of these arrangements, introducing new commands for the Masters of Soldiers for Africa and Italy after their recovery, and establishing a Master of Soldiers for Armenia out of the older eastern field command. By the end of his reign there were over 25 regional commands behind the frontiers and deeper inland, serving both as military and police force for internal matters, stretching from that for Scythia in the north-west Balkans through the Middle east and Egypt to Mauretania in north-west Africa. The real differences between field troops and garrison units were not always very clear, mainly because of cross-postings from one type of army to the other, and because so many field units were more or less permanently based in and around garrison cities.
Justinian established a strategically very important new field command, known as the quaestura exercitus (loosely translated as ‘regions allocated to the army’), similar to that of a Master of Soldiers, but whose commander was entitled quaestor. This command included the troops based in the Danube frontier zone (the provinces of Scythia and Moesia II), but included in addition the Asia Minor coastal province of Caria along with the Aegean islands. The aim was to supply the Danube divisions by sea from an Aegean hinterland and thus relieve the oppressed local population of the frontier regions and their hinterland from the burdens of supporting a large military force. In addition to the regular corps, the empire maintained substantial numbers of allied forces: Arab clans and tribes were essential to the empire’s strategic arrangements in the east, and were subsidised with food, cash, vestments, imperial titles and weaponry.
The emperors had also several guards units based in or near the imperial palace, or in the districts about Constantinople. The most important were the Schools, or scholaepalatinae and the excubitores. The former were organised in seven divisions of 500 heavy cavalry soldiers. Originally elite shock units recruited largely from German peoples, they had become by the middle of the fifth century little more than parade units. In their stead as active guards the Emperor Leo I (457-474) recruited the latter, a much smaller elite unit of a mere 300 men. Imperial naval forces were relatively limited - several small flotillas maintained along the Danube, a fleet was based at Ravenna, and a squadron at Constantinople.
Imperial strategy was based on a first line of defence that consisted of a linear frontier screened by fortified posts, major fortresses and a connecting network of minor fortified positions. This was supported by a second line made up of a reserve of mobile field units scattered in garrison towns and fortresses across the provinces behind the frontier. By the end of Justinian’s reign the gap between the different functions of the ‘frontier’ and ‘field’ armies had been narrowed, for the reasons noted already, and in the 560s and 570s garrison units seem to have reinforced and fought alongside field army units. In effect, the late Roman army was a relatively expensive force of very variable quality, which consumed a large proportion of the state’s fiscal revenue each year, both in respect of cash payments, as well as in terms of equipment and maintenance in kind for troops on campaign.
The frontier was considerably strengthened from the later fifth century into Justinian’s reign as political and military priorities evolved and as new threats developed. Typical of such efforts on the eastern front is the fortress of Dara. This fortress (also called Anastasioupolis, mod. Turkish Oguz) was built by the Emperor Anastasius I in the years 505-507, to serve as a military base on the Roman-Persian frontier, where the doux of Mesopotamia was based c. 527-532. The magister militum per orientem may also have been established there from 540 to 573, when the city was taken by the Persians. Retaken in 591, it fell again to Persian forces in 604, was recovered at the end of the great Persian war in 628, and fell to the Arabs in 639. Situated on the road from Nisibis (mod. Nusaybin) to Marde (mod. Mardin), some 15 miles north-west of Nisibis, it stood at the head of a dry watercourse which, in the winter season, flows down to the Khabur river farther south.
The terrain of the region is fairly barren, consisting for the most part of an undulating plain dissected by several shallow dry watercourses and occasional ridges, the strategic importance of Dara was considerable, since it covered a major route into Roman Mesopotamia and beyond into both north Syria or north-westwards into Asia Minor.
Defensive building in the east was characterised by fortresses such as this, and by the maintenance or construction of large numbers of fortlets and defended outposts, linked by a network of military roads, which acted to screen the desert frontier and points of ingress and egress. Under Justinian, and following the recovery of the North African provinces, a similar screen of major fortified cities accompanied by outposts, watchtowers and fortlets was established there, designed to inhibit the depredations of the Berber peoples to the south (or to police their movements within imperial territory). In Italy and the Balkans the pattern was very different. In the Balkans, because of the penetration of the Danube front by Slav groups and other raiders, and in Italy as a reflection first of the long-drawn-out warfare with the Goths and the ensuing fighting with the Lombards, no cohesive linear system was possible. Instead, the government, in the form of the local military and civil authorities, seems to have promoted the development of a dense pattern of small fortified sites which could support both local military defence and defend the interests of agrarian production and local trade. This meant on the one hand a reduction in the importance to the state of some of the major urban centres, but on the other an increase in the numbers and in the strategic and economic relevance of medium - and small-scale sites, which were generally situated in more easily-defended locations, served as local centres of exchange and production, and possibly also fiscal administration. What might be termed a medieval pattern of small, highly-localised fortified centres was beginning to evolve in response to the changed circumstances and military needs of the times.
World History
