Early Life and Formation
Cyril was born in Egypt around 376 into an illustrious and pious Christian family. His uncle Theophilus, Patriarch of Alexandria, oversaw his upbringing and education in scripture, Christian doctrine, and the secular learning of the day. By tradition he spent several years in his youth among the monks of the Nitrian desert, in the monastic settlement associated with Saint Macarius, before returning to the service of the Alexandrian Church.
Theophilus ordained Cyril to the diaconate and appointed him to preach. Cyril accompanied his uncle to Constantinople in 403 for the synod known as the Synod of the Oak. When Theophilus died in 412, Cyril was chosen to succeed him as Patriarch of Alexandria, taking up an office he would hold for thirty-two years.
The Nestorian Controversy
After Nestorius became Archbishop of Constantinople in 428, he objected to the long-established title Theotokos for the Virgin Mary, preferring Christotokos and teaching a sharp distinction between the divine and human in Christ. Cyril regarded this as a denial of the true union in the one incarnate Christ, who is at once God and man.
Cyril first sought to recall Nestorius from his error through private and pastoral letters, and when this failed he set the dispute before the wider Church, writing to the clergy of Constantinople, to the Emperor Theodosius II, to Pope Celestine of Rome, and to other bishops. His Second and Third Epistles to Nestorius became central documents of the controversy, the latter appending twelve anathemas against the doctrines he condemned.
The Council of Ephesus
The Emperor Theodosius II convened the Third Ecumenical Council at Ephesus in 431 to resolve the dispute. With Cyril presiding and some two hundred bishops gathered, the council examined and condemned the teaching of Nestorius, who, though present in the city, declined to appear before it. The council deposed Nestorius and affirmed that Mary is rightly called Theotokos, because the one born of her is God the Word made man.
The proceedings were contested and Cyril himself was for a time placed under arrest amid the conflict between the parties, but the council's judgment against Nestorius stood and the deposed archbishop was sent into exile. The defense of the unity of Christ articulated at Ephesus became a permanent part of the Church's confession.
Writings and Repose
Cyril was a prolific theologian and exegete. Among his works are commentaries on books of the Old Testament and on the Gospel of John, the dogmatic treatise known as the Thesaurus, discourses against the Arians, dialogues on the Holy Trinity, and his writings against Nestorius, including the Five Books against Nestorius. These works secured his place among the most authoritative of the Church Fathers.
Cyril reposed in 444. The Orthodox Church commemorates him on June 9 and, together with Saint Athanasius the Great of Alexandria, on January 18. In the tradition he is honored as a Pillar of Faith and is numbered among the great teachers and defenders of Orthodox doctrine.
