Quite different in kind were the bishoprics established as Christianity spread, in the fifth, sixth and seventh centuries, into the non-Roman or post-Roman world. Early medieval Ireland and England were not significantly urban and hence a new kind of bishopric was required, one that was not city-based, indeed, one that might be without a fixed seat, adapted to the needs of a people (gens) or, in Ireland, a monastic congregation. The early Anglo-Saxon bishoprics thus tended to shift with the varying political patterns and to take their titles from an ethnic group or a region rather than a city. Hence we find ‘bishops of the West Saxons’ before there were ‘bishops of Winchester’, ‘bishops of the Hwicce’ before ‘bishops of Worcester’. In this way the institution of the episcopate adapted itself to social conditions very different from those of its birth. Indeed, one of the main features of the ecclesiastical history of the British Isles in the eleventh and twelfth centuries was the re-establishment of the territorial, city-based episcopacy that had come to be the Latin model or norm in place of this early medieval non-urban model.