Constantine I, also known as Constantine the Great (272–337), was a Roman emperor from 306 to 337 AD. He was the first Roman emperor to convert to Christianity and is notable for ending the persecution of Christians in the Roman Empire. Constantine moved the capital of the empire from Rome to Constantinople, which remained the capital of the Byzantine Empire for over a thousand years. He also reformed the Roman military, introduced a new currency system, and promoted Christianity throughout the empire. He is considered one of the most important figures in Roman history and is often referred to as the "first Christian emperor."