And since the holy Virgin hath borne after the Flesh God united Personally to the Flesh, therefore we do say that she is also Mother of God, not as though the Nature of the Word had the beginning of It’s existence from flesh, for It was “in the beginning and the Word was God, and the Word was with God” [John 1:1], and is Himself the Maker of the ages, Co-eternal with the Father and Creator of all things: but (as we have already said) seeing that He united human nature to Himself Personally and underwent fleshly birth from the very womb, not as though by any necessity or for the sake of His own Nature needing the Birth in time and in the last times of the world, but in order to bless the very beginning of our being and that, because a woman bare Him united to the flesh, the curse against our whole race might at length be stopped, the curse which sends to death our bodies of earth, and the words, “in sorrows shalt thou bear children” [Gen. 3:16], through Him abolished, He might manifest that true which is uttered by the Prophet’s voice, “Death in its might is swallowed up, and God again removed every tear from off every face.” [Isa. 25:8 LXX] For this reason do we say that He economically blessed marriage itself also and when bidden in Cana of Galilee went thither together with the holy Apostles.

These things have we been taught to hold by the holy Apostles and Evangelists and the whole God-inspired Scripture, and by the true Confession of the blessed Fathers: to all of them must thy Piety too assent and consent without any guile.

The things which it is necessary that thy Piety anathematize have been annexed to this our Letter:

1. If any one confess not that Emmanuel is in truth God and that the holy Virgin is therefore Mother of God, for she bare after the flesh the Word of God made Flesh, be he anathema.

[St. Cyril the Alexandria, Third Letter to Nestorius]