Battle of the Milvian Bridge

The Battle of the Milvian Bridge occurred in 312 AD, on October 28. Constantine I fought against Maxentius, the ruler of Italy, and was victorious at this battle, thus ending the Tetrarchy and becoming the one and only Emperor of Rome. According to some scholars, he attributes his victory to a vision he had had previously. He allegedly said that Jesus Christ had appeared to him in a dream, telling him to go to his soldiers and mark all of their shields with the sign of the cross. According to Eusebius, because of this dream of his, Constantine made all of his soldiers fight under the cross. This is often marked as Constantine's conversion to Christianity, but it is also a subject up for debate.