High Quality Content by WIKIPEDIA articles! The Battle of the Milvian Bridge took place between the Roman Emperors Constantine I and Maxentius on 28 October 312. It takes its name from the Milvian Bridge, an important route over the Tiber. Constantine won the battle and started on the path that led him to end the Tetrarchy and become the sole ruler of the Roman Empire. Maxentius drowned in the Tiber during the battle.