☧Constantine the Great
Original nameConstantine the Great
The first Christian emperor, who carried Christianity from persecution toward state faith
Those Who Fought the Map Into Being · Generals & Conquerors
Battle of the Milvian BridgeEdict of MilanConstantinopleLegalizing Christianity
Who they are
Constantine the Great (c. 272–337) was one of the most far-reaching emperors in Roman history, the first to convert to Christianity. In 312 AD, before the Battle of the Milvian Bridge outside Rome, he is said to have seen a vision of the cross with the revelation "by this, conquer," then won a great victory and united the West. The next year, with the eastern emperor, he issued the Edict of Milan, declaring Christianity legal and ending persecution — a sect crucified under Nero only decades before now set out on the road to becoming Rome’s state faith. He also built a new capital, "Constantinople" (modern Istanbul), on the Bosphorus, shifting the empire’s center east and laying the foundation of the Byzantine Empire that would last a thousand years. It was in his hands, one might say, that the two worlds of classical Rome and Christian Europe made their handover.
Primary sourcesEusebius, Life of ConstantineLactantius, On the Deaths of the Persecutors
Key stories
"By This Sign You Shall Conquer"
On the eve of the decisive Battle of the Milvian Bridge in 312 AD, legend says Constantine saw in the sky a vision of the cross (or the Greek monogram ☧) with a line of words: "By this sign you shall conquer." He had his soldiers paint the sign on their shields and won a sweeping victory. Whatever the truth of the vision, he credited the win to the Christian God, and it became the starting point of his support for Christianity — the outcome of one battle indirectly rewriting the whole religious map of the West.
Building St Peter's on Peter's Tomb
After his conversion, Constantine raised the first St Peter’s Basilica on the Vatican hill, where the apostle Peter was, by tradition, martyred and buried. A Roman emperor used the power of the empire to raise the holiest sanctuary for a religion a former emperor had persecuted. Twelve centuries later that church was torn down and rebuilt into the St Peter’s we see today, built with the hands of Michelangelo and Bernini — but its root was laid by Constantine.
Version differences
Constantine’s "vision of the cross" comes from the accounts of Christian historians, and its authenticity, along with the timing and sincerity of his own conversion, is long debated; this site states the dispute.
Echoes today
Below are how modern works borrow or reinterpret this name or story — not the original material. The two differ, so keep them apart.
Founder of Christian Rome and ByzantiumThe Edict of Milan legalized Christianity and is seen as the turning point from persecution toward Europe’s mainstream faith; the Constantinople (modern Istanbul) he built lasted a thousand years as the Byzantine capital, deeply shaping Eastern Europe and the Orthodox world.