Children and slaves first

In the reign of Constantine, whose conversion to Christianity in AD 310 set the entire Roman world on a course to becoming Christian, a Palestinian scholar named Eusebius pondered the reasons for the triumph of his faith. Naturally, he saw behind it the guiding hand of God; but he did not rest content with that as an explanation. The purposes of heaven were to be traced in the patterns of earthly history. ‘It was not merely as a consequence of human agency that the greater part of the world’s peoples came to be joined under the sole rule of Rome — nor that this should have coincided with the lifetime of Jesus.’ A global faith, Eusebius argued, had been rendered possible by a globalised age.

Today, the question of how and why a crucified criminal from an obscure corner of the Roman empire had come to be enshrined, within a bare four centuries, not just as a divine patron of the empire, but as one who had decisively routed all his rivals for the title, toppling gods from their ancient thrones and terminating their priesthoods, is one that — understandably — continues to preoccupy historians.