Town and countryside are contrasting, even opposed ideas: one of those doublets which have dominated European thought since antiquity. Our vocabulary of ‘politics’ and ‘civilization’ bears ample testimony to the deep hold that the prejudices of the townsmen of antiquity have established over our language and our thinking. Sometimes, even in antiquity, those prejudices would be turned on their head: the town, the exclusive milieu of culture, refinement and rational human behaviour, could become, as for instance in the eyes of a Jewish rabbi of the third century the seat of iniquity, set up to extort and to oppress. Whatever the attitude one took to the town, the dichotomy of town and countryside became almost a category in the Kantian sense in terms of which modern Europeans have come to perceive the world around them. With Max Weber it became a fundamental category of sociological understanding, with Rostovtzeff of historical analysis, especially of the ancient world in its decline; and in the hands of William Frend—the Rostovtzeff of ecclesiastical history—it showed its power to illuminate, even to transform, the study of ancient heresy and schism. ‘The church in town and countryside’ might be thought to extend the franchise of a notion which has already had too wide and at times, as some would have it, perhaps even a baleful, influence. But both the value of the notion of town and country as an interpretative tool for the ecclesiastical historian, and its limitations, its liability to obscure and to distort, will, I hope, become clearer in the course of discussion.