Frontier army of the late roman empire in the mid-4th c. a.d. (case of Isauria and the Rhine frontier): on the ways of territorial deployment of military units

Introduction. During the whole 4th c. the Late Roman frontier militaryunits constantlytook part in military campaigns against different enemies of the Empire, hovewer the author of this paper asks the question how precisely frontier military units managed their service, i.e. which functions they exercised and how they interacted to local civilian population of the province where they stood in. The author believes that a set of functions depended foremost on the location landscape. Methods and materials. The author applies the comparison approach,i.e. compares the peculiarities of two regions where the frontier armies stood: Isauria at the southeast of Asia Minor (mountain landscape) and Upper Germany at the Rhine frontier (mainly plain territory). The source accounts are “The Life of St. Conon of Isauria” (hagiography), an important inscription of Julian the Caesar (future Emperor Julian the Apostate) from Upper Germany (epigraphy) and the work of Ammianus Marcellinus “The Deeds” ( Res gestae ). Analysis. The author compares evidence on the military arrangement of two provinces and considers how their frontier units defended these lands from external and internal enemies, how theyinteracted to local population and how precisely they located in its forts. Conclusions. As a result the author concludes that the Roman administration could not place a large number of regular military units in Isauria, because this province had not enough fertile plain lands, this region suffered from the lack of food supply. The hard and cruel mountain landscape enforced to make the bands of irregular city militia - in the case of Isaurian assaults citizens formed military detachments, which were temporarily attached to regular units called vexillations. In contrast, at the Rhine frontier, where there were enough fertile flat lands, the Roman administration might place many regular units and, moreover, this region received detachments from expeditionary troops. In other words, the Roman administration had enough food supply to maintain a high number of regular frontier garrisons.