Cyril of Alexandria

Cyril succeeded his uncle Theophilus as Patriarch of Alexandria in 412 and governed that great see for thirty-two years. When Nestorius, archbishop of Constantinople, refused to call the Virgin Mary Theotokos, 'Birthgiver of God,' and so divided Christ into two subjects, Cyril rose as the champion of the unity of Christ's person, teaching that the eternal Word Himself was truly born, suffered, and died in the flesh for our salvation. He presided at the Third Ecumenical Council at Ephesus in 431, which vindicated the title Theotokos and deposed Nestorius. A prolific writer, he left profound commentaries on Scripture, dogmatic treatises, and the paschal homilies of his see. He reposed on June 27, 444; the Church commemorates him on June 9 and again on January 18 with St Athanasius, honoring him as the Seal of the Fathers.

Cyril of Alexandria is also one of the Church Fathers — read their biography, works, and verse-by-verse commentary.