The Division of Dacia into Provinces: Borders and Military Organization

The structure that was put in place by Marcius Turbo and probably further developed by his successor, Iulius Severus (120–126), affected the province's borders and military organization and had an impact on the neighbouring Barbarian territories, the Banat, Oltenia, and Wallachia. Although recent archaeological finds have thrown some light on this process, many details — intra-provincial boundaries, the procurators' sphere of authority, and whether the fortified posts along the left bank of the Danube were subordinated to Dacia or to Moesia — remain the subjects of debate. It must have been, at the latest, in this period that units of the Lower Moesian army's units were withdrawn from Wallachia; thus, some of the land occupied during the Dacian Wars was relinquished. A region west of the Olt River was constituted into a new province called Dacia Inferior (Lower Dacia). The province was governed by a procurator of knightly rank, for no legion was stationed there, and {1-68.} enjoyed a certain autonomy in internal affairs. It was bounded in the southwest by the Danube, in the northwest by Dacia Superior, and by a line running from Dierna (Orsova) to the southeast Carpathians. Its eastern border may have followed either the line of camps along the Olt, or a fortified line, some 25–35 kilometres farther east, running roughly parallel to the Olt, and called the Limes Transalutanus.

Prior to the division, the remainder of Dacia — with the exception of the northern part — was renamed Dacia Superior (Upper Dacia). It encompassed central Transylvania and the eastern Banat all the way to the eastern Carpathians. The transfer of the legion IIII Flavia to Moesia Superior left only one legion in Dacia Superior, the XIII Gemina, stationed at Apulum. The province's governor also commanded the legion. Since, according to the prescriptions of Roman administration, former consuls could only rule provinces with more than one legion, Dacia Superior was in subsequent decades administered by officials of the next lower rank, i.e. senators, who became consuls only at the end of their terms as governor.

Another new province was carved out in the northern part of Dacia, which corresponds to northern Transylvania, and named Dacia Porolissensis after the important military camp at Porolissum (Mojgrád); this may have been done at the time of the 118 reorganization, and certainly before 124. As in Dacia Inferior, no legion was stationed in the province, and thus administration was entrusted to a procurator of knightly rank. In military matters, the governor of Dacia Superior had supervisory responsibilities over Dacia Inferior and Dacia Porolissensis. Dacia was thus divided into three parts.

After the first 10–15 years of military occupation, a more or less definitive structure of defence and administration had emerged. Rome withdrew its troops from regions of lesser importance. The three Dacian provinces' borders to the north, east, and west were {1-69.} part of the empire's defensive perimeter. The line was drawn to according to topographic features as well as in anticipation of the provenance of enemy action, and it influenced, in turn, the enemy's strategies.

In the mountains and valleys of Dacia Porolissensis, a line of military camps, which were at times located in close proximity to one another, protected the province against raids from the north by free Dacian and Dacianized Celtic tribes (Anartii, and later by German tribes (Buri). period. In the west, the border ran north from the Aranyos valley along the Bihari, Gyalu, and Vigyázó mountains; no trace has surfaced of the camps in this region. Farther north, the valleys of the Sebes-Körös and the Szamos were guarded by camps at Gyalu (Gilău) and Sebesváralja (Bologa). The northern frontier, where narrow valleys offered a natural access for attackers, was guarded by the long ridge of the Meszes Mountain and an unusually close-set line of camps (Vármező-Buciumi, Magyaregregy-Românaş, Romlott-Romita, and Porolissum's two camps, on the heights of Pomet and Csitera). The Cikó pass was defended by a camp at Tihó (Tihău). Between and in front of the camps, a dense network of watchtowers overlooked the frontier. Farther east, the frontier followed the inner range of the Haragos, Ilosva and Lápos mountains, with camps at Alsókosály (Căşeiu = Samum?) and Alsóilosva (Ilişua), veered southwards along the Borgó and Kelemen Alps, and finally ran along the inner, western range of the eastern Carpathians (Alpes Bastarnicae: Tabula Peutingeriana). Camps were established at Jád (Iad-Livezile) and Óvárhely (Orheiul Bistriţei), on the southwestern slopes, as well in the Maros valley at Marosvécs (Brîncoveneşti); the latter was Dacia Porolissensis' southernmost camp on the eastern frontier.

In the plains of the Banat, the principal threat to Dacia Superior came from Sarmatian Jazyges, and the only known border fortifications were in that southern region. To the west, a forward line of camps was constructed, along the road from the Lederata (Palanka) {1-70.} pontoon bridge to Tibiscum (Zsuppa, Jupa), at Gerebenc (Grebenac), Arcidava (Varadia), Versec (Vršac, Yugoslavia), Centum Putei (Szurduk, Surduc), Bersovia (Zsidovin, Berzovia) and Aizis (Furluk, Fîrliug). There were fortified camps along another road, running from Dierna, just to the west of the Drobeta bridge, to Tibiscum, at Pretorium (Mehadia), Ad Pannonios (Teregova), and Agnaviae (Závoly, Zăvoi). Northward, towards the Maros valley, there were no camps, for the Ruszka Alps provided a defensive shield. The Maros valley itself was protected by military camps at Micia (Vecel, Veţel), Felsővárosvíz (Orăştioara de Sus), Bucsum (Bucium), and Csigmó (Cigmău), as well as by the camp of the Dacia Superior legion at Apulum, in the central part of the province. The frontier north of the Maros valley was marked by the Érc and Bihari mountains.

The north-eastern frontier of Dacia Superior ran along the westernmost ranges of the eastern Carpathians, including the Görgényi Alps and the Hargita mountains, and had camps at Mikháza (Călugăreni), Sóvárad (Sărăţeni), Énlaka (Inlăceni), Székelyudvarhely (Odorhei Secuiesc), and Homoródszentpál (Sînpaul). In the region of the eastern front, the borderline separating Dacia Superior and Dacia Inferior is not clear.

With regard to Dacia Inferior, its northeastern and eastern borders also constituted the frontier of the empire. In the east, the line ran along the western ranges of the eastern Carpathians, with camps at Olthévíz (Hoghiz), Oltszem (Olteni), Komolló (Comolău), and Nagyborosnyó (Boroşneul Mare). The Ojtoz pass was guarded by the forward camp at Bereck (Breţcu). To the southwest, the Olt valley was guarded by camps at Kissink (Cincşor), Földvár (Feldioara), and, later, by a camp at Caput Stenarum (Bojca, Boiţa) which secured the Vöröstorony pass. Since there were no natural defences south of the Carpathians, a dense line of camps had to be built on the Oltenian Plain to guard against attack from the Sarmatian Roxolani. Two lines of defence were constructed on the {1-71.} eastern border. The inner one ran along the Olt River; according to epigraphs at Bivolari, Racoviţa, Copăceni, and Rădăcineşt, the camps were probably rebuilt in stonework towards the end of Hadrian's reign.[26]26. CIL III, 12,601, 12,605, 13,795, 13,796. There were camps of normal scale (that at Slăveni measured 169 by 190 metres) as well as a series of smaller forts (Copăceni, Titeşti, Bivolari, Sîmpotin, Stolniceni, and Enoşeşti). Some 25–30 kilometres east of the Olt line, the Romans added a parallel, outer line of defence on a north-south axis, the 'Limes Transalutanus'. Pending excavations, the date of its construction can only be guessed at. The general assumption is that the Limes Transalutanus was constructed around 200 A.D., and abandoned by the middle of the 3rd century. Even without excavation, the traces found at certain camps (Săpata de Jos, Urluieni, Băneasa) of two forts, side by side, indicate two construction periods, for it is unlikely that they would have been in use simultaneously. This suggests that the camps in the outer line were used for a longer period of time, and that they may have been constructed before 200. There were earthworks, some three metres high, at a distance of 150–300 metres on the eastern approaches to the camps. Towards the northern end, the outer defensive line, like the Olt line, turns northeastward with the camps at Pürkerec (Purcăreni) and Cîmpulung; the two ends of the Törcsvár pass were guarded by forts at Rukkor (Rucăr) and Barcarozsnyó (Rîşnov).

The fact that Dacia was a geographical salient, deep into Barbaricum, determined the layout of its military defences. It needed protection from attack in three directions, along extensive borders. No camps were built where passage was barred by impassable mountains. For defence in depth, additional camps were built along river valleys away from the frontier. In addition to those along the Maros, camps were built to protect the road to Napoca from northern attack at Gyalu (Gilău), near the junction of the Hideg- and Meleg Szamos rivers, and near the Kis-Szamos river at Szamosújvár (Gherla). Camps at Maroskeresztúr (Cristeşti) and Segesvár {1-72.} (Sighişoara) protected the valleys of the Maros and the Nagy- Küküllő, respectively, against attack from the east. The camps in Oltenia and the Banat also served to protect lines of communication with the inner empire. As in the case of other provinces, Dacia's frontier fortifications clearly demarcated the reach of the province and of the empire.

There were some 80 military camps in Dacia. Indication of the dates of construction has yet to be unearthed, but it is likely that a few of them were used for only a short period. The large overall number is explained by the fact that on the Olt limes and the Transalutanus, only a few camps were of normal size, but they were linked by dozens of smaller posts, and one military unit probably manned several of these. In 164 A.D., the 15 camps in Dacia Porolissensis were manned by 3 mounted and 12 infantry regiments, or some 11,500 soldiers, not counting the legions' special detachments. It has been estimated that in the 2nd century, the total military complement in Dacia — including the legions — stood at 45,000–50,000.

So far, the earliest form of fortification, consisting of earthworks and palisades, has been observed in the unearthed remains of fifteen camps. Under Hadrian and Antoninus Pius, some of the camps were partially or fully reconstructed in stonework; others were not upgraded until the early years of the 3rd century.

The military structure protecting Rome's domain between the mouth of the Tisza River and the Black Sea acquired final shape during the reign of Hadrian. Prior to the conquest of Dacia, Moesia's short Danube border, between the mouth of the Tisza and two of its tributaries the Almum (Lom) and the Ciabrus (Cibrica), was defended by two legions: the IIII Flavia legion in Singidunum (Belgrade) or Ratiaria (Arčar, Bulgaria), and the VII Claudia legion in Viminacium (Kostolac). To the east, the border of Moesia Inferior had been guarded by three evenly-spaced camps, that of the V Macedonica at Oescus (Gigen), of the I Italica at Novae {1-73.} (Svishtov), and of the XI Claudia at Durostorum (Silistra). The conquest of Dacia led to changes in this regular pattern of defence. Dacia's Danubian border with the empire no longer required substantial defence, but the three legions remained on guard along the long border of Moesia Inferior. Therefore, the V Macedonica legion was transferred from Oescus, on the Dacian frontier, to the Danube delta at Troesmis (Igliţa). The legion IIII Flavia was moved from Moesia Superior's short Danubian border to join the occupation forces in Dacia. The camp at Ratiaria was shut down; there, and at Oescus, colonies were founded by Trajan. No evidence has surfaced concerning the camps of auxiliary units, but it is clear that the military complement on Dacia's border with the empire was reduced considerably.