Between 451 and 590 Christianity was the official religion of the emperors, though in some of the outlying portions of the empire its hold was slight. The eastern churches held the Balkans, Asia Minor, Egypt, Palestine, Syria and Mesopotamia; western Christianity was mainly a Mediterranean religion, strong in Italy, in north Africa before the Vandal invasions, in the Rhone valley and in Spain. In north Gaul, Britain and Ireland a portion of the population were converted, but neither the empire nor Christianity had made any progress beyond the Rhine. In east and west Christianity had conquered the towns before the countryside: its organisation had developed while the Christian population consisted mainly of city groups, and from the cities it had spread slowly outwards over the countryside. By the middle of the fifth century the normal unit of church government was the city group of Christians, headed by the bishop and his “familia” of clergy. The see or sphere of the bishop’s authority included a larger or smaller territory round his city, very small in the east and Italy where cities were plentiful and Christianity was old, very large in the west where conditions were the opposite. This sphere of authority was known usually as the “parochia” or parish of the bishop. Episcopal sees had already become grouped in provinces, under the authority of the
metropolitan or bishop of the mother see. His authority was exercised in a supervision of episcopal elections, (which were made by the clergy, nobles and people of the parochia under the direction of neighbouring bishops summoned to perform the obsequies of the late bishop), and in the summons and presidency of the provincial synod. At these synods bishops and representatives of their clergy attended, and canons or rulings on points of discipline and doctrine were laid down by the metropolitan after discussion in the synod: these canons were the chief standard and rule for the governance and life of the church.