The Battle of Milvian Bridge was a decisive military engagement fought on October 28, 312 AD, near Rome, at the Milvian Bridge. It marked a pivotal moment in the history of the Roman Empire, primarily because of its impact on the rise of Christianity and the political landscape of the time.
The battle was part of the Civil Wars of the Tetrarchy, a period of political instability following the retirement of Diocletian and his co-emperor Maximian. The Tetrarchy, a system of government introduced by Diocletian, was meant to divide power between four rulers to stabilize the empire but eventually led to conflict among the Caesars and Augusti.
Constantine marched on Rome with an army significantly smaller than Maxentius'. Before the battle, Constantine reportedly had a vision or dream where he was instructed to mark the Chi-Rho symbol on his soldiers' shields, which he interpreted as a sign from the Christian God promising victory. This event is often cited as the turning point for Constantine's conversion to Christianity.
Maxentius decided to engage Constantine outside the walls of Rome, at the Milvian Bridge over the Tiber River. His plan was to trap Constantine against the river, but this strategy backfired:
Constantine's victory was complete, and he entered Rome in triumph, becoming the undisputed ruler of the Western Roman Empire.