Constantine was a Roman emperor who reigned from 306 to 337 AD. Constantine grew up in the military while his father ruled over Rome. When his father passed away while at war in Britain Constantine decided to stay there for awhile. While he was gone people got mad and said that other people should rule over Rome even though Constantine was the rightful heir to the throne. This ended causing a war to breakout that war was called the Battle of Milvian Bridge. Constantine had a vision that he should fight with the symbol of a cross on his shield and he did. After winning the war he became a Christian. Constantine ended up making it illegal to persecute Christians in the Roman Empire.