The beginning of the sixth century saw Anastasius (491–518) on the imperial throne, ruling an empire that was still thought of as essentially the Roman empire, coextensive with the world of theMediterranean. Although Anastasius ruled from Constantinople over what we call the eastern empire, the western empire having been carved up into the ‘barbarian kingdoms’, this perspective is ours, not theirs. Through the conferring of titles in the gift of the emperor, and the purchasing of alliances with the wealth of the empire – wealth that was to dwarf the monetary resources of the west for centuries to come – the barbarian kings could be regarded as client kings, acknowledging the suzerainty of the emperor inNew Rome, and indeed the barbarian kings were frequently happy to regard themselves in this light (see below, p. 198). The discontinuation of the series of emperors in the west, with the deposition ofRomulusAugustulus in 476, was regarded by very few contemporaries as a significant event; the notion that east and west should each have their own emperor was barely of a century’s standing, and the reality of barbarian military power in the west, manipulated from Constantinople, continued, unaffected by the loss of an ‘emperor’ based in the west. The empire that Anastasius ruled was still the Mediterranean world as it had been since classical times in more than just a political sense: it consisted of a world whose basic unit was the city which, with its hinterland, formed a self-sufficient economic and even cultural unit. Although shorn of the political powers of the old city-state, the notables of the city still exercised considerable political influence and the provincial governors, appointed from the same social class as these notables, frequently found it more effective to recognise local influence than to challenge it. The cities – with fora, theatres, courts and opportunities for education – formed the seedbed for the educated elite who held posts in the imperial administration, often returning to the cities to enjoy the essentially rural wealth generated by their country estates. All this was to change from the sixth century onwards, though there is a good deal of debate about the rate at which this change took place. The city was also the basic unit of the Christian church. From the end of the second century Christianity, which from the start had been a predominantly urban phenomenon, had developed an organisation based on the city and its hinterland; it was led by a single officer, called a bishop, who was appointed for life.1 With the gradual Christianisation of the Roman empire from the fourth century onwards, the bishop became a considerable figure among the notables of the city. He was sometimes appointed defensor civitatis, that is the leader or ‘judge’ of the city, and he regularly exercised the functions of this post, even when not officially appointed to it. Despite the decline of the city as an economic and cultural entity,2 the link between bishop and city was to continue. Christianity had never been a particularly peaceful religion, and the importance it attached to correctly formulated beliefs, combined with its increasing social influence as fewer and fewer inhabitants of the empire resisted the pressure to embrace Christianity, meant that well before the sixth century Christian belief had become both a cause of social, political and cultural divisions, and a means of articulating them.Modern historians are shy of regarding religious belief and practice as the reason for social and political divisions, and in general they may well be right, but it is undeniable that in this period division was often expressed and understood in religious terms. As we shall see, issues of religious difference are woven into the narrative of sixth-century history. It is important to understand the basis for these differences before going on to consider other explanations for social, political and cultural divisions that were expressed in these terms. Religious conflict is a theme to which we shall often return.