How Christian was Constantine?


In AD312, so the legend goes, the Roman emperor Constantine saw a vision in the sky on the eve of battle: a Christian emblem and the message ‘Conquer with this’. In reality, it almost certainly didn’t happen that way, but Constantine nevertheless became the first Roman emperor to convert to the new religion, and his promotion of the faith led to a transformation of the ancient world. In my Twilight of Empire series of novels, I try to show how this religious and cultural transformation might have appeared, seen through the eyes of a man far from keen on the changes.

But was Constantine genuinely a committed Christian, or was he using religion for his own ends? Ever since the historian Jacob Burckhardt first suggested it in the 1850s, many have considered that the emperor’s conversion might have been motivated by cynical opportunism and ambition for total power, rather than by genuine spiritual belief.


The evidence for this view takes three main parts. Firstly, Constantine was not baptised until he was on his deathbed, which might suggest a certain ambivalence about the faith beforehand. Secondly, long after the supposedly crucial date of AD312, Constantine’s coins continued to display images of traditional Roman gods – Jupiter, Mars, and in particular the sun god, Sol Invictus. Thirdly, Constantine apparently made few moves to suppress or abolish traditional beliefs, and even constructed new temples in his city of Constantinople, where a statue depicted him wearing the radiate crown of Sol.

The first of these objections can be dismissed fairly easily. In early Christianity, deathbed baptism was quite common. It was, at the time, the only way of ridding oneself of sin – a one-shot soul-cleanser. For a man in Constantine’s position, obliged to take many morally dubious decisions (to say the least) while conquering and ruling a vast empire, it made sense to delay baptism as long as possible. Apparently, the emperor originally intended to have himself baptised in the River Jordan, just like Christ himself. In the event, he fell ill and died before he reached the Holy Land; but once he had finally undergone baptism he dressed himself in a simple white tunic and lay down to await death, content that he would enter heaven in a state of complete purity.

It is true, meanwhile, that Constantine issued many coins with pagan images and motifs. After AD305, when he first seems to have adopted Sol Invictus as his personal deity and protector, images of the sun god are most common. But his coins also show Mars, Hercules and Jupiter. Would a convinced Christian have allowed such a thing?

Bronze coin issued by Constantine in AD317. The reverse shows the sun god Sol Invictus, referred to as 'Companion of the Emperor'.

Bronze coin issued by Constantine in AD317. The reverse shows the sun god Sol Invictus, referred to as 'Companion of the Emperor'.

Interestingly, images of Sol disappear from Constantine’s coinage after AD319, and, following the final defeat of his last rival, the eastern emperor Licinius, in AD324, non-Christian imagery vanishes from the coinage altogether. It was the battle of Chrysopolis in that year, rather than Milvian Bridge twelve years previously, which really saw Constantine’s religious beliefs come to the attention of the world.

Christianity in the early fourth century was far from being a majority faith in the empire; perhaps only about 10% of Romans followed it. So it is perhaps unsurprising that Constantine continued to support certain aspects of the traditional religions, particularly during times of civil war, when a more vigorously anti-pagan policy could have provided ammunition for his enemies. But a letter to the eastern provinces, quoted by the biographer Eusebius and apparently written after the defeat of Licinius, makes it plain what Constantine thought of the old beliefs: “With regard to those who will hold themselves aloof from us, let them have, if they please, their temples of lies: we have the glorious edifice of truth…”

There was nothing all that ‘unRoman’ about Christianity by this stage. The traditional polytheistic customs of the Roman past had been declining in influence for decades, replaced by a multitude of new cults and philosophical beliefs, many of eastern origin, that tended towards a monotheistic outlook. The Christian hierarchy had been thoroughly Romanised, and by the early 4th century there was little cultural and no ethnic difference between a Roman Christian and a follower of more traditional beliefs.

Nor was it unusual for an emperor to identify himself with a particular god. Both Diocletian and Maximian, the senior emperors of the ‘tetrarchy’ that had preceded Constantine, had done just that: Diocletian named himself Iovius, the ‘man like Jupiter (or Jove)’, the living image of the king of the gods; his colleague Maximian was Herculius, the ‘man like Hercules’. Constantine seems initially to have adopted the sun god Sol Invictus in the same way – especially after his supposed vision of Apollo in Gaul some time in AD309-310. Ten years later, perhaps, he may have come to see Christianity as a more powerful version of Sol worship – from the Sun God to the Son of God, we might say, in one easy step!

Whatever Constantine’s own beliefs might have been, few people would have noticed an immediate difference after the Battle of Milvian Bridge. It was only during the final campaign against Licinius that we hear of Constantine praying before battle, ordering his troops to carry a Christian standard (in opposition to the pagan images still apparently used by Licinius) and even, according to the later writer Sozomen, purging the army of the rituals and the iconography of traditional religion altogether.

While certain of Constantine’s acts following his victory over Licinius – dismantling temples and apparently even melting down cult statues for coinage – may have had a financial motive, many of the emperor’s other religious and social measures appear to have been driven mainly by his own personal religious belief. Constantine, it seems, wanted a single unified religion for the empire, with himself at its head; the schisms and heresies of the church apparently pained and confused him far more than the ongoing beliefs of the traditionally-minded. "For while the people of God, whose fellow-servant I am,’ he wrote in the same letter quoted above, ‘are thus divided amongst themselves by an unreasonable and pernicious spirit of contention, how is it possible that I shall be able to maintain tranquillity of mind?

In his public declarations, then, Constantine appears to have been quite certain about his commitment to Christianity. He not only convened several church councils to decide knotty problems of dogma, but also composed the enormous speech known today as the Oration to the Saints; this would have taken a full two hours to recite, and probably served no political purpose at all – we can only pity the courtiers and ministers who had to listen to it! Meanwhile, in his reply to the Donatists after the Council of Arles in AD314, Constantine wrote that "I myself must be judged by Christ" (qui ipse judicium Christi expecto).

But while we can say with some confidence that Constantine at least believed himself to be a committed Christian, certainly after AD324 and probably before that too, working out what sort of Christian he might have been is a lot more difficult. The oration I mentioned above is rather confused in some aspects, and suggests that the emperor’s faith might have been quite unorthodox. Identifying himself with Christ, just as Diocletian and Maximian had identified themselves with Jupiter and Hercules, would have been seen as deeply heretical and perhaps blasphemous. But with Constantine ruling supreme over the Roman empire, and promoting Christianity with such vigour, it is unlikely that any of the bishops and other clerics that gathered around him would have taken it upon themselves to try and ‘correct’ the emperor’s beliefs!

The hand from the colossal statue of the emperor Constantine in Rome; originally it would have held a sceptre, probably featuring a Christian monogram.

The hand from the colossal statue of the emperor Constantine in Rome; originally it would have held a sceptre, probably featuring a Christian monogram.