Bp. of Cyrrhus in Syria from 423. He soon became involved in the Christological controversy between Nestorius and Cyril of Alexandria. In a polemical work against Cyril, he maintained a duality in Christ and accepted the title of Theotokos only in a figurative sense. Though he abandoned this position in a later confession of faith in 448, he was nevertheless deposed by the Council held at Ephesus in 449 (the Latrocinium) and forced into exile. The new Emp. Marcian summoned him to the Council of Chalcedon (451), where he reluctantly anathematized Nestorius. He apparently spent his last years peacefully administering his diocese. A century later his writings against Cyril were the subject of the ‘Three Chapters Controversy’ and were condemned at the Council of Constantinople (553).
His surviving works include a fine Christian apology (the Graecarum Affectionum Curatio); the Eranistes, which is a treatise against the Monophysites; and a Church History continuing the work of Eusebius to 428, as well as exegetical works which are among the finest specimens of the Antiochene School.