‘I too am a bishop, appointed by God.’ Constantine’s portrayal of himself was presumably meant to amuse the bishops at his court. His knowledge of Greek was competent enough to realise that episkopos could be a good pun: they were ‘bishops’ for internal ecclesiastical affairs, and he was ‘overseer’ of everything else. This quip suggests that the first Christian emperor respected bishops and churchmen. It was also rather pointedly hollow humour. In the early fourth century Christianity was not widespread or influential in Roman society, and most likely there were comparatively few bishops and clerics. At the famous Council of Nicaea in 325 over 200 bishops attended. These bishops were mostly from the Eastern provinces, with only a handful from the West. Constantine had made an advantageous choice, because in the early fourth century most people were still outside the church.

The patronage of Constantine and subsequent emperors during late antiquity transformed bishops and their roles in totally unforeseen ways. In earlier centuries the number of bishops had been limited; now almost every city in the empire had a bishop, and classical cities survived as episcopal sees. Since these bishops and many of their lesser clerics were recruited primarily from the class of local notables, increasingly the ecclesiastical hierarchy attracted men away from service as municipal magistrates. In earlier centuries bishops had been loosely connected through letters, visits and occasional councils; now they developed a more extensive organisation that was modelled on the imperial administration. The consolidation of this new hierarchy led to a heightened emphasis on new attitudes about clerical service, such as ambition and competition, that seemed at odds with Christian ideals.