Arius (Berber: Aryus ; , AD 250 or 256–336) was a Christian presbyter and ascetic of Libyan birth, possibly of Berber extraction, and priest in Alexandria, Egypt, of the church of the Baucalis. His teachings about the nature of the Godhead, which emphasized the Father's divinity over the Son, and his opposition to what would become the dominant  Christology, Homoousian Christology, made him a primary topic of the First Council of Nicea, convened by Roman Emperor Constantine in AD 325.