Rome and the Sasanian Empire in the fifth century A.D: a necessary peace

Since Ardashir’s victory over the Parthians in A.D 224 to his successors’ eventual defeat at the hands of the Arabs in 651 the Roman and Sasanian Empires had been bitter and deadly rivals. Throughout Late Antiquity the Roman-Sasanian relationship was dominated by competition; a constant battle for imperial prestige, military supremacy, cultural influence and economic advantage. In the course of their relationship Ctesiphon, the Sasanian capital, was sacked by Roman forces, the Roman emperor Valerian was captured and taken prisoner, Julian the Apostate was killed by Sassanian forces in his infamous campaign of 363, and the great Roman city of Antioch had been captured and razed. Yet in this seemingly never-ending imperial struggle the fifth century stands out as a period of unprecedented peace between the imperial rivals. It is the aim of this thesis to analyse what made the fifth century a unique period of peace. This thesis seeks to expand on current scholarship on the fifth-century Roman-Sasanian relationship, which has focused on the investigation of specific and individual events, by taking a more holistic approach. In this regard, all aspects of the relationship, military conflicts, frontier zones, barbarian threats, religious issues, economic considerations and the development of diplomatic contacts, will be analysed in order to identify what pushed the two empires towards a peace and, more importantly, how this peace was maintained in the face of old hostilities and traditional antagonism. Viewing the Roman-Sasanian relationship as merely one part of the wider late antique world, not as something unique and separate, will also be a key component of this investigation. Central to the aim and approach of this thesis is the use of political realism, a theory for understanding international relations, to reveal the motivations and pressures that both empires faced in this period that pushed them towards peace. In this regard, it will be argued that the Roman and Sasanian overriding desire and goal of ensuring their own safety and security in an anarchic world in the face of the new and dangerous threats posed by the ascendant Huns, Hephthalites and Vandals was the underlying motivation behind the fifth-century peace. It was the threat posed by these groups that forced a shift in Roman-Sasanian relations towards the accommodation that both needed to survive the turbulent fifth century. As such, it was these new threats that stimulated the development of imperial diplomacy in the fifth century that allowed the two empires to mediate their traditional casus belli and maintain peace throughout this period. This diplomatic development allowed them to reach new and innovative diplomatic solutions to their problems in the frontier zones of Arabia and Armenia