At the beginning of the sixth century, the Eastern Roman emperor, more confident of his security on his northern frontiers, began behaving in a more belligerent fashion towards his counterpart in Sasanian Iran. Violent conflict began in 502 and escalated during the rest of the century. Slow-moving siege warfare in the Fertile Crescent alternated with truces, while proxy conflicts continued at each end of the frontier. These hostilities drew both powers deeper into the Arabia Peninsula, with three important consequences. The first was the continued expansion of the Arabian federations in the north of the Peninsula, on the empires’ desert frontiers. The second was further heightening of the political importance of religion, with various forms of Christianity and Judaism being markers of identity and political affiliation. Third, escalating conflict between the two powers led, at the end of the century, to the collapse of the northern federations and contributed to the weakening of Himyar. These events were the context for the expansion of the influence of West Arabian groups and the formation in the early seventh century of a new religious and political community under the leadership of the Prophet Muhammad.

Arabia, Rome and Iran in the Sixth Century

In the sixth century, the Romans replaced a balance of alliances on their Syrian Desert frontier with the sponsorship one ruling clan, the Jafnids, and their allies, known collectively as the Banu Ghassan, or ‘Ghassanids’. This change in Roman policy was probably a response to the military effectiveness of the Sasanians’ alliance with the Nasrid kings of al-Hira, in Iraq. In about 530, Emperor Justinian (r. 527–65) promoted the Jafnid al-Harith b. Jabala to ‘the dignity of a king’, in the sense of a local ruler, acknowledged by the Romans. Papyrus documents from Petra, in modern Jordan, show that members of the Jafnid elite were significant figures on the Roman frontier, called upon to arbitrate in local disputes. Greek inscriptions show that the Jafnids participated in the wider political culture of the Roman Empire while asserting their own religious and cultural autonomy.