L’Empire des Théodoses et les regna Orientis (379-450): politique militaire et diplomatie impériale à l’égard des foederati orientaux

Between the end of the reign of Valens (377-378) and the death of Theodosius II (450), the Roman Empire, in its Pars Orientis, developed a politicy of active diplomacy towards both the realms of the Causasian area (Armenia, Iberia, Colchis), and the groups of Sarakênoi from the limes Orientis. The establishment of foedera with “barbarian States”, which were, by definition (in most cases), outside of the Empire though still under the imperial influence, was conditionned by various factors: geopolitical considerations (such as rivalries with the Persian Empire, the presence of the Huns north of the Danube, relations with the Saracenoi Blemmyes and Noubades groups on the eastern borders, military interventions of the oriental Empire in the western part in 430-440), troubles inside the Empire since the Battle of Adrianople (granted settlement of the Goths as a consequence of the Gothic War of 379-382, the effects of this situation through the first decades of the 5^th century, other barbarian groups being allowed intra fines imperii), and military imperatives (fighting against the gothic inner ennemy, and restoring imperial military power, on the short- and medium-term). Despite the limitations of the sources, it is nevertheless possible to speak of foederati by proposing a nuanced definition of the term which differentiates foederati extra fines imperii from foederati intra fines imperii on the political and diplomatic level on the one hand, and which makes a distinction on the military level (according to the nature of the fighting service provided to the Romans) on the other hand, between those barbarian foederati enlisted as regular units of the imperial army, and those barbarian foederati engaged by ethnic contingents with some tactical speciality. Close analysis, however, affirms the difficulty of identifying the foederati and their various types, and the necessity of adopting a level of interpreting the sources which is cautious, adaptable, pragmatic, and which is not blindly and rigidly systematic.