ABSTRACT
Rome’s relations with her strongest eastern rival had never been stable. The Parthian Empire of the Arsacids, founded by Arsaces c.250 bc, was subject to the same disruptions as the Roman Empire: internal unrest, external threats and the ever-present possibility of usurpation. Arsaces himself had won his throne by force, driving out the previous dynasty of the Achaemenids and taking over their territories by right of conquest. Just as in the Roman world, there was always the threat of dynastic squabbles and military risings; the Parthian Empire was a conglomerate of different peoples and tribal groups, not all of whom submitted easily to Parthian rule.1 Vassal kings sometimes rebelled, aiming for independence or alliance with other powers, and nomadic tribes on the borders occasionally invaded the more settled territory. From the late Republic onwards a mutual tension between the two powers had occasionally erupted into war, and Rome always kept one eye on events in the east. Great expeditions had been mounted against the Parthians, sometimes in response to a perceived threat and sometimes in response to direct provocation, as for instance when Mark Antony’s generals were attacked in Syria, Judaea and Asia Minor. These Parthian expeditions had always cost the Romans a great deal in money and personnel, and were not always successful. Some were disastrous, most infamously that of Marcus Licinius Crassus, who was defeated and killed by the Parthians in 53 bc. Antony fared no better when he tried to dash through Armenia and come upon the Parthians from the north. Augustus avoided war altogether, and by a much-celebrated diplomatic tour de force he managed to retrieve the Roman military standards that Crassus had lost. Diplomacy did not suit all Emperors and all circumstances.
