Of the many books on Constantine that have recently appeared to mark a series of anniversaries, this is the one that pretends to the greatest intimacy with its subject. Constantine, we hear, was ‘a deeply complex man of seemingly boundless energy’ (2); in later life he may not have been ‘proud of the man that he had been in 303’ (95), having come in the meantime to ‘sense, or hope, that he had a divine friend’ (128). He sought out human friends who ‘shared his own values’ (274), and his ‘self-imposed celibacy’ after the execution of Fausta reveals that, ‘however serious the quarrel’ which caused him to put her to death in boiling water, he ‘never ceased loving his wife’ (247). Nevertheless, this is not a hagiography; and it is indeed considerably more than a biography. There are few books from which readers new to the history of the late Roman world can learn so much so quickly, and fewer still which carry such a dense apparatus of scholarship in the notes. The lives, campaigns and policies of Constantine's predecessors, from Gallienus to Diocletian, are described with a fluent precision that betokens years of study and reflection. The significance (and occasional insignificance) of Constantine's own laws is illustrated by succinct but comprehensive observations on the position of slaves, the function of rescripts and the ubiquity of sacrifice. These sketches form the background to a portrait of an emperor who never allowed his private faith to peep through the statesman's mask which no other ruler had worn so ably since the first years of the Tetrarchy. Conscious that his religion was not shared, or was only speciously professed, by the majority of his subjects, he did not fall prey to the ‘sickness’ of the ageing Diocletian: he did not try to abolish paganism, continued to clothe himself and his god in the solar imagery that was now prescriptive, and did not imitate his own subjects who had begun to speak of Sunday as the ‘Lord's Day’. If he was not the designing hypocrite that Burckhardt supposed him to have been, he was not the intolerant despot that some scholars suppose every Christian to be.

In discussing Constantine's conversion — ‘a journey over time and in his own mind’ (156) — Potter rightly argues that if we read our sources in chronological order we see a calculated process of aggrandizement which makes it impossible to reconcile them without omitting much that each witness deemed essential to his story. He might have added that no attempt to identify one or more of Constantine's dreams with a solar halo is half as cogent as the writings of Immanuel Velikovsky and Erich von Daniken on the miracles of the Old Testament. Positivists will be more content with the handling of the Oration to the Saints, which P. dates (as many now do) to a.d. 325, though without the vituperative certainty that characterizes the best-known defences of this position in English. My own proposal that it was intended for Rome in a.d. 315, and therefore for delivery in Latin, is courteously but illogically dismissed on the grounds that most of the sources from which it quotes are in Greek (329). The references to Plato are hardly quotations and, thanks to Cicero, one did not need Greek to read the Timaeus; a Latin version of the eighth Sibylline Oracle, preserving the acrostic for the most part, is attested by Augustine, and in any case the Greek is quoted by Constantine's contemporary Lactantius, who undoubtedly wrote in Latin. P. also holds, with Barnes, that the tyrant whose defeat is commemorated in ch. 25 can only be Licinius, since only he inherited the whole army of Diocletian; but on the same grounds we are bound to hold that he cannot be Licinius, since the latter could not plausibly be described as a usurper. Historians in search of a date are too apt to approach this speech as though it were written by one of themselves; but orators lie, and the things which were done among them as ensamples were not written for our admonition.

As a theologian, I would like to know how Constantine could have hoped to reconcile contending parties in a.d. 325 by the assertion that the Son and the Father were distinct ousiai — the very doctrine (if expressed in those Greek terms) which was condemned a few months before the Nicene Council at the synod of Antioch (222). Again, the bitterest enemy of Marcellus of Ancyra would not have wished to see him anathematized for teaching that ‘the world would end’ (283): the heresy lies in holding that the passing away of this world will be followed by the abdication of Christ. The theology of Constantine is occasionally both subtle and original, leaving no doubt that, like Henry VIII and both our Cromwells, he was every crooked inch a Christian. P.'s concern, however, is with Constantine the emperor, and though he does not quote the phrase, he understands exactly what was implied by his protagonist's resolution to be ‘bishop (or overseer) of those outside’.