Cyril of Alexandria hath been styled the Doctor of the Incarnation. For he was concerned with the Nestorian heresy from its inception, and denounced the same to Saint Pope Celestine I, and at the Council of Ephesus in 431, at which the heresy was solemnly condemned , he presided as the representative of the Roman See. And the rest of his life was given over the defence of the truth that in Christ Jesus there is one divine Person. * Cyril was born of distinguished parents, and was the nephew of Theophilus, Patriarch of Alexandria, whom he succeeded in that office. He was a man of learning, and of much vigor and determination, and he turned all his powers to the extirpation of heresy and unbelief. His sternness in these matters made him many enemies, even amongst those of orthodox practice, but chiefly he was assailed by the followers of Nestorius, who at one time secured a sentence of excommunication against him as a troublemaker, to which many even of the orthodox bishops assented, which same was later declared null and void. * He wrote much regarding the Faith, and was emphatic in his teaching concerning the Eucharist, whereof he said : We receive it, not as common flesh (which God forbid), nor as the flesh of a man sanctified and associated with the Word, but as indeed the lifegiving and very Flesh of the Word himself. But chiefly he is remembered for his teaching that Mary is the Mother of God, which title the Council of Ephesus acceded to her. At length he died a holy death, in June of the year 444, and the 32nd of his episcopate, but in the west his feast is kept in February.
Collect: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 our Lord. Amen.