Constantine I (272-337); also known as Constantine the Great and Saint Constantine; was the son of Emperor Constantius. His father sent him east to serve under Emperors Diocletian and Galerius; spending some time in the court of the latter. After his father died in 306 CE; Constantine was proclaimed his successor and emperor by his army at Eboracum (York).He at first remained officially neutral in the efforts of Emperor Galerius to defeat the usurper Maxentius; but after Galerius' death; Constantine was dragged into the conflict. He eventually defeated Maxentius in 312 CE; and then fought against his erstwhile ally; Emperor Licinius; for sole control of both western and eastern portions of the Roman Empire. Licinius was defeated in 324 CE; and Constantine became emperor of a united empire.Constantine enacted many reforms strengthening the empire; ending the tetrarchy system and restructuring government. He became the first emperor to claim conversion to Christianity; and he called the First Council of Nicaea in 325 CE; overseeing the profession of the Nicene Creed. He renamed Byzantium to Constantinople after himself; which would become the new capital. He died in 337 CE.