St. Cyril (born c. 376) is one of the great Greek fathers of the Church. He was the Church’s defender against Nestorius, who denied the unity of Christ’s person. If this heresy had succeeded, Mary would not be called the Mother of God.
Along with St. Athanasius and St. Augustine, he was one of the greatest defenders of orthodoxy in the history of the Church. His greatest achievement was the successful outcome of the ecumenical council at Ephesus (431), to which Pope Celestine had appointed Cyril as his papal legate. In this council two important dogmas were defined; namely, that there is but one person in Christ, and that Mary truly and rightly can be called the Mother of God (Theotokos).
His writings show immense depth and theological clarity, which were so necessary at a time when heresies were threatening the orthodox teaching of the Church.
St. Cyril died in 444 A.D., after having been bishop of Alexandria for thirty-two years.
O God, who didst strengthen thy blessed Confessor and Bishop Saint Cyril, invincibly to maintain the divine motherhood of the Blessed Virgin Mary: vouchsafe that at his intercession we, believing her to be indeed the Mother of God, may as her children rejoice in her protection; through the same Jesus Christ thy Son our Lord, who liveth and reigneth with thee, in the unity of the Holy Spirit, ever one God, world without end. Amen.
