ABSTRACT
In the 30 years that followed the Sasanian overthrow of the Parthians, Roman power on the Euphrates and in Mesopotamia was seriously challenged for the first time. In the centuries before, conflict between Rome and the Parthians had often developed due to the ongoing struggle for control in Armenia. While Armenia had not become a Roman province, except for a brief period under Trajan, Rome exercised considerable power and influence there even before Pompey’s establishment of the province of Syria. The Parthians claimed hegemony over the kingdom, based on longstanding political and cultural links.1 While the rhetoric of each side consistently claimed hegemony in Armenia, reality saw compromise struck between the two powers in various guises. On numerous occasions both sides attempted to repudiate this compromise. Trajan, Lucius Verus and Septimius Severus all responded militarily to Parthian attempts at asserting control in Armenia and turned these ventures into much larger military undertakings, which resulted in invasions of Parthian territory. Under all three emperors, Roman control in formal and less formal ways came to extend further across the Euphrates towards the Tigris. The extension of control under Verus and Septimius Severus was long-lasting, and while Trajan’s advances were short-lived they set a precedent that emperors would seek to emulate for centuries. The formalization of Roman power in Mesopotamia and Osrhoene late in the second century AD, with Mesopotamia established as a garrisoned province, added another element to the conflict between Rome and its eastern neighbour. From this time, a permanent Roman military presence extended to the upper Tigris, formally establishing a considerable extension of Roman power during the previous century into regions that had been more traditionally aligned with the Parthian Empire.2
