Athanasius the Confessor or, primarily in the Coptic Orthodox Church, Athanasius the Apostolic, was the 20th bishop of Alexandria (as Athanasius I). His intermittent episcopacy spanned 45 years, of which over 17 encompassed five exiles, when he was replaced on the order of four different Roman emperors. Athanasius was a Christian theologian, a Church Father, the chief defender of Trinitarianism against Arianism, and a noted Egyptian leader of the fourth century.