Flavius Valerius Constantinus, also known as Constantine the Great, was a Roman emperor who ruled from 306 to 337 AD. The name "Constantinus" can be replaced with a variety of synonyms such as "the Great", "Emperor of Rome", "Flavius", "Valerius", or simply "Constantine". His rule was marked by a number of significant events including the conversion of the Roman Empire to Christianity, the founding of the city of Constantinople, and the defeat of rival emperors Maxentius and Licinius. Constantine has been portrayed as a complex figure, revered by some for his contributions to Christianity and Roman history, and controversial for his political and military tactics.