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
Figure 5.1 Relief sculpture of Ardashir unhorsing Artabanus V at Naqsh-i Rustam near Persepolis (photo: Jeff Tillitzki).
Internal political developments in the third century AD in both the Roman and Iranian empires changed the nature of conflict on Rome’s eastern frontier in the first half of the century. The overthrow of the Parthi-ans was an important factor in this as was the beginning of a period of instability at a number of different levels in the Roman Empire. Roman power and influence, which had advanced considerably in the previous century, was now seriously challenged by the Sasanians, particularly in Mesopotamia. Rome’s power in Syria and Cappadocia, areas that had both been Roman provincial territory for centuries, also came under threat.
The royal family of Parthia ruled Iran for more than 350 years until the early third century AD when a revolt took place culminating in a great battle c. 223/224, in which the Sasanian Persian prince Ardashir defeated the Parthian king Artabanus V.3 Ardashir then became Shahanshah, King of Kings. A consolidation of this activity followed in which the Sasanians eventually established hegemony over the lands of Iran; Armenia, though, remained a source of dispute. Armenia mostly remained under the kingship of relatives of the Parthian dynasty, who were supported by Rome until the kingdom was divided between Rome and Persia c. 387.4 Prior to the Sasanian overthrow, there is little evidence for the Parthians mounting major military campaigns to reassert their earlier influence and control over Mesopotamia, Osrhoene and the middle Euphrates beyond the Khabur.5 The most significant effort in this respect took place early in the joint reigns of Marcus Aurelius and Lucius Verus; that attack was driven back with considerable success by Roman forces. There were, however, ongoing Parthian attempts to maintain influence and power in Armenia and we have seen that these were often met by major Roman military offensives. The situation changed dramatically soon after the Sasanian Persian overthrow of the Parthians as the new regime conducted a number of attacks on Mesopotamia, the middle Euphrates and Roman territory further west.
Ardashir mounted raids on Roman provincial territory in Syria and Mesopotamia in 230, but these were driven back by Severus Alexander a few years later. It was not until 237/238 that Ardashir’s most significant invasions of Roman territory took place, and it was only when Persian forces attacked Mesopotamia that the Roman literary sources, namely Dio and Herodian, demonstrated any knowledge of the significant change that had taken place in the government of Iran. The main focus of both writers was on the internal problems which they claimed the Roman Empire faced, with little attention paid to any military strength or capability of Ardashir. This suited the purposes of the last section of Dio’s History, whose stated aim in that section was to show how from the death of Marcus Aurelius to the reign of Severus Alexander, ‘history now descends from a kingdom of gold to one of iron and rust’.6 We will see later that while authors of the contemporary and local Syrian text, Oracula Sibyllina XIII, recognized the power and determination of the Sasanians in the 240s and 250s, the focus in later Roman and Byzantine texts was also on Roman weakness and internal difficulties in the third century.
World History
