★ Saint Cyril, Archbishop of Alexandria
Cyril was born in Alexandria about 376 of an illustrious Christian family and was the nephew of Patriarch Theophilus, by whose care he was given a thorough education in scripture, classical literature and the Greek fathers. As a young man he spent some six years among the monks of the Nitrian desert, where he absorbed the spiritual discipline and the dogmatic formation of the Egyptian church. Ordained reader and then deacon by his uncle, he succeeded him on the patriarchal throne in 412 and guided the church of Alexandria for thirty-two years.
The struggle that gives Saint Cyril his place among the great teachers of the Church was provoked by Nestorius, who was raised to the see of Constantinople in 428 and began to teach that the Virgin Mary should be called only Christotokos, mother of Christ, but not Theotokos, mother of God. Cyril answered with letters and treatises whose precision shaped the Christology of the universal Church, insisting that the one Christ is one person, the eternal Word made flesh, and that Mary therefore truly bore in her womb God incarnate. The third Ecumenical Council, gathered at Ephesus in 431 under Cyril's presidency, condemned Nestorius and confirmed the title Theotokos. Cyril afterwards laboured to restore communion with the more cautious Antiochene bishops, and the Formula of Reunion of 433 brought a peace celebrated in his famous letter "Let the heavens rejoice." He fell asleep in the Lord on 9 June 444, leaving an immense body of biblical commentaries, dogmatic treatises and letters that have nourished the Church ever since.