"We confess, then, our Lord Jesus Christ, the only begotten Son of God, perfect God and perfect man, of a rational soul and a body, begotten before all ages from the Father in his Godhead, the same in the last days, for us and for our salvation, born of Mary the Virgin according to his humanity, one and the same consubstantial with the Father in Godhead and consubstantial with us in humanity, for a union of two natures took place. Therefore we confess one Christ, one Son, one Lord. According to this understanding of the unconfused union, we confess the holy Virgin to be the Mother of God because God the Word took flesh and became man, and from his very conception united to himself the temple he took from her."  - The Council of Ephesus, Formula of Union, 431 AD