Norman Baynes opened his 1929 Raleigh lecture to the British Academy reflecting on the difficulty of making sense of Constantine. Constantine’s life and work don’t just raise historical problems (making sense of the evidence) but a problem of the philosophy of history:

“To my mind, at least, all attempts to explain away Constantine as the natural outcome of the previous history of Rome have failed completely. Constantine can only be satisfactorily interpreted in terms of the Zeitgeist if the Zeitgeist is arbitrarily fashioned in the likeness of Constantine. The more closely Constantine’s life and achievement are studied, the more inevitably is one driven to see in them an erratic block which has diverted the stream of human history. It may be true that by A.D. 311 the imperial policy of persecution of the Christians had proved a failure . . . but this failure could not carry with it the implication that it was the duty of a Roman Emperor to disavow Rome’s past as himself to adopt the faith professed by perhaps one-tenth of his subjects.”

Constantine is “an intractable individual” who was “not merely the creation of the past” but “a new beginning wich was in such large measure to determine the future of the Roman world.”

One can almost excuse Eusebius his excessive enthusiasm. For someone who had seen Christians flayed like sacrifices, Constantine must have seemed nothing less than a miracle.