grew up in what the historian A. H. M. Jones described as ‘evil times’. Roman rule had expanded fast since it first rolled into Greek territories in the second century BC. Five hundred years later, the huge, unmanageable empire was on the brink of collapse, threatened by invasions, civil wars, famines and plagues, with rival armies proclaiming new emperors almost too fast to keep count.
Religion was also in flux. The traditional Roman gods had long since merged with the Greek pantheon: Rome’s chief god, Jupiter, was identified with the Greek Zeus, while the goddess Aphrodite took on attributes of Venus, and the Greek solar deity Helios became associated with the Roman sun god, Sol. These planetary gods occupied a central position in daily life, not just for religious rituals and sacrifices but fortune-telling, too, as astrology, imported from Babylon, became popular across the Greco-Roman world.
By the first century the planets even ruled over the calendar, with the introduction of a seven-day week – also probably originating in Babylon – starting with Saturn (Saturday), followed by the sun (Sunday), moon (Monday), Mars, Mercury, Jupiter and Venus.2 As Rome’s empire grew, however, so did its pantheon, as the Romans happily adopted the gods of the provinces they conquered. The new faith of Christianity had to carve out a place in a society already ‘crammed full of deities’, as one historian put it, from the mother-goddesses Artemis of Ephesus and Isis of Egypt (associated with the star Sirius) to the Persian sun god, Mithras.
It took the iron hand of Diocletian, an ex-commander of the imperial bodyguard, to restore order. After becoming emperor in 284, he emphasised Rome’s traditional gods, and punished the Christians who refused to worship them. He also divided the sprawling empire into two parts, each led by senior and junior partners in a four-emperor system known as the Tetrarchy. Diocletian and Maximian (Maxentius’s father) ruled the east and west, respectively. They both retired in 305; Constantine’s father, Constantius, took over from Maximian, and when he died in England the next year, his army proclaimed Constantine his successor. But the Tetrarchy system had created multiple claimants for the various thrones, including Maxentius, and over the next few years Constantine had to negotiate his way through a series of battles and betrayals as the rivals vied for power.
In 310, after he defeated Maximian in Marseille, Constantine ordered his army to march off the main road to visit a temple sanctuary.3 There, according to one contemporary account, the emperor had a divine vision in which he was promised military victories and a long rule. The bearer of the message wasn’t a flaming cross, though, but the classical god Apollo, who was often associated with the sun.
Roman leaders traditionally insisted that their power came from Jupiter, a deity with origins in the older Indo-European sky-god Dyaus. But some claimed links with a supreme solar deity, seeing themselves as a kind of conduit that reflected the sun’s rays on Earth. According to Jonathan Bardill, author of Constantine, Divine Emperor of the Christian Golden Age, it’s a tradition that goes back to the Greek-speaking Ptolemaic kings who ruled Egypt after Alexander the Great, in turn influenced by the ancient Egyptian pharaohs and their worship of the sun god Ra. In the first century BC, Julius Caesar wore a radiate crown; his heir Augustus (Rome’s first emperor) erected an obelisk brought from Egypt as a giant sundial. In the first century AD, Nero erected a colossal bronze statue of himself as the sun.
These efforts did not generally end well. When Marcus Aurelius Antoninus, a teenager from Emesa, Syria, succeeded the throne through family connections in 218, he was a priest at his local temple, where worship of the Syrian sun god Elagabalus centred on a large, cone-shaped meteorite. He took the stone to Rome and worshipped it daily, ‘dressed in silk robes, a lofty tiara, and cheeks painted red and white’. He was assassinated four years later, and his mutilated corpse was dragged through the streets. Aurelian, who became emperor in 270, had slightly more success when he tried to replace Jupiter with the cult of Sol Invictus, the ‘Unconquered Sun’.4 Its central festival was Sol’s birthday, 25 December, a few days after winter solstice, when the sun resumes its journey north and the days start to lengthen towards spring. Aurelian was assassinated too, five years into his reign, but the cult of Sol Invictus survived him.
It’s not clear why Constantine chose to follow his ill-fated predecessors with his solar vision; perhaps he wanted to distance himself from the traditional religion of the Tetrarchy. But from 310, all of Constantine’s mints produced coins that featured Sol, described as ‘companion of the emperor’, in his characteristic pose: standing naked with his right hand raised and wearing a radiate crown. When Constantine set out to liberate Rome in 312, says Bardill, ‘it was with the sun-god as his guardian’.
Did he then have a second vision that converted him to Christianity? Some researchers have suggested that the ‘flaming cross’ Constantine reportedly saw was a solar effect called a sun dog, which occurs when sunlight is refracted by ice crystals in the atmosphere and can make the sun appear cross-shaped. But there doesn’t necessarily have to be a meteorological explanation. Roman leaders often used reports of dreams and visions to encourage their troops or claim divine support. (When Augustus entered Rome following Caesar’s murder, it was said that a circular rainbow formed around the sun.) Constantine’s cross in the sky is probably just another version of the Apollo story, retold later with a Christian spin.
Nonetheless, after Constantine defeated Maxentius, his religious policies did shift. Christians had been targeted on and off since Nero’s time, culminating in Diocletian’s ‘Great Persecution’, during which anyone who refused to sacrifice to the pagan gods was imprisoned or executed. Constantine reversed that in 313, allowing the empire’s inhabitants to worship whichever god they chose. In 321, he decreed that the Christian day of worship (Sunday) would be an official day of rest for Roman citizens, and after he gained sole control of the empire in 324, he started using Christian symbols on his coins. He removed or repurposed pagan statues and built a series of important Christian churches, including the Church of the Holy Sepulchre in Jerusalem, over the supposed locations of Jesus’s crucifixion and empty tomb, still seen as Christianity’s most holy site.
Constantine also supported Christians financially and involved himself intimately in the running of their church. In May 325, he convened hundreds of bishops from across the empire for the First Council of Nicaea, the first attempt to agree a common doctrine for all of Christianity. The early Christian bishop and historian Eusebius describes him sitting in the middle of the great hall in purple and gold robes, ‘like some heavenly messenger of God, clothed in raiment which glittered as it were with rays of light’. He bullied the squabbling bishops into near unanimity, helping to build a powerful, unified ‘Catholic’ church.5
This conventional history, however, is mostly gleaned from accounts by Christian authors such as Eusebius. Other sources reveal that there’s more to the story, just as with Constantine’s vision and victory arch. For years after his defeat of Maxentius, for example, Constantine kept making coins that featured Sol, though he eventually stopped around 324. And although Christians observed a rest day on Sunday, in his decree Constantine didn’t refer to it as ‘the Lord’s Day’, as Christians did. He introduced the law ‘in veneration of the sun’. In 330, at his new, supposedly Christian, capital of Constantinople, Constantine erected a giant statue of himself on a 37-metre-high column of purple porphyry. It depicted him naked with a radiate crown, facing east towards sunrise. The statue was felled by high winds in 1106, but literary sources preserve the inscription: ‘For Constantine who is shining like the sun.’
In other words, Constantine didn’t give up his solar beliefs. But how could he follow both religions, when Christianity expressly forbids the worship of other gods? Some clues come from his letters, in which he describes, for example, the saving power of God’s ‘most brilliant beams’, and says that God ‘held up a pure light’ through his son. Historians such as Bardill argue that Constantine never really converted from paganism to Christianity at all. Instead, he simply joined the two, seeing the Christian God as a sort of supreme solar deity whose rays were spread on Earth by Christ. By deliberately blurring the boundaries between the two
