Describing Constantine’s deathbed baptism, Alan Kreider ( The Change of Conversion and the Origin of Christendom ) observes that “it is impressive that the church leaders required Constantine to go through all this. For many years they, faced with a potential recruit of no less power and eminence than the emperor . . . nevertheless held him at arm’s length. And when they eventually received him, they did so only on the condition that he go through the well-tried conversion processes of the church. We do not know what postbaptismal teaching (mystagogy) Constantine received. But apart from that, it is striking that Constantine’s journey of conversion, rushed and truncated thought it was, had all the requisite stages.”

The priesthood of the plebs works both ways: Plebs receive the same baptism as patricians; emperors humble themselves to be initiated like slaves.