born 0441; 375
died June 27, 444; Western feast day June 27; Eastern feast day June 9
Christian theologian and bishop.
He became bishop of Alexandria in 412. Zealously orthodox, he closed the churches of the Novatians, a heterodox sect, and expelled the Jews from Alexandria. His greatest doctrinal conflict was with Nestorius over the nature of Jesus ; Cyril emphasized the unity of Jesus' divine and human natures while Nestorius emphasized their distinctness. Cyril condemned Nestorius at the Council of Ephesus (431), only to be condemned himself by bishops who supported Nestorius. Eventually Nestorius was declared a heretic and a compromise on Christ's nature restored peace to the church (433).