Constantine Statue at York © N.S. Gill

On this day in A.D. 312, the Roman Emperor Constantine was victorious in battle for control of the Western Roman Empire against the Roman Emperor Maxentius. The battle is known as the Battle at the Milvian Bridge, a stone bridge across the Tiber River. Constantine is said to have had a vision the preceding night telling him that he would win under a certain sign that included the appearance of a cross set against the sun and certain words in Greek that translate into Latin as: in hoc signo vinces 'you will win under this sign.' This sign and the following victory are credited with convincing Constantine to convert to Christianity, which he did, but not immediately.

Also see

• Constantine
• About.com's Military History Guide's blog on The Milvian Bridge