Constantine I[g] (Latin: Flavius Valerius Constantinus; 27 February c. 272 – 22 May 337), also known as Constantine the Great, was a Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity.[h] He played a pivotal role in elevating the status of Christianity in Rome, decriminalizing Christian practice and ceasing Christian persecution. This was a turning point in the Christianization of the Roman Empire. He founded the city of Constantinople and made it the capital of the Empire, which it remained for over a millennium.
Born in Naissus, in Dardania within Moesia Superior (now Niš, Serbia), Constantine was the son of Flavius Constantius, a Roman army officer of Illyrian origin who would become one of the four emperors of the Tetrarchy. His mother, Helena, was a woman of low birth, probably from Asia Minor in modern Turkey. Later canonised as a saint, she is credited for the conversion of her son in some traditions, though others believe that Constantine converted her. Constantine served with distinction under the Roman emperors Diocletian and Galerius. He began his career by campaigning in the eastern provinces (against the Persians) before being recalled in the west (in AD 305) to fight alongside his father in the province of Britannia. After his father's death in 306, Constantine was proclaimed as augustus (emperor) by his army at Eboracum (York, England). He eventually emerged victorious in the civil wars against emperors Maxentius and Licinius to become the sole ruler of the Roman Empire by 324.
