St. Cyril of Alexandria: And since the holy Virgin hath borne after the Flesh God . . .

St. Cyril of Alexandria“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 Its 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.”

— St. Cyril of Alexandria, Third Letter to Nestorius