2. The Chalcedonian Statement. The third and fourth ecumenical councils (Ephesus, 431, and Chalcedon, 451) settled the question of the precise relation of the two natures in Christ's person. The decree of the Council of Ephesus, under the lead of the violent Cyril of Alexandria, was merely negative, a condemnation of the error of Nestorius, and leaned a little toward the opposite error of Eutychea. Nestorianism triumphed temporarily in the " Robber Synod " of Ephesus, in 449, under the lead of Dioacurus of Alexandria, who inherited all the bad, and none of the good, qualities of his predecessor, Cyril. But Dyophysitism reasserted itself; and Dioscurun and Eutyches were condemned by the Council of Chalcedon. This council gave s clear and full statement of the orthodox christology as follows (for Greek and Latin text and. notes, cf. Schaff, Creeds, ii. 62-65):

"Following the holy Fathers, we all with one consent teach men to confess one and the same Son, our Lord Jesus Christ, the same perfect in Godhead and also perfect in Manhood; truly God and truly man, of a reasonable [rational] soul and body; consubstantial [coequal] with the Father according to the Godhead, and consubstantial with us according to the Manhood; in all things like unto us, without sin, begotten before all ages of the Father according to the Godhead, and in these latter days, for us and for our salvation, born of the Virgin Mary, the Mother of God, according to the Manhood; one and the same Christ, Son, Lord, Only-begotten, to be acknowledged in two natures, Inconfusedly, unchangeably, indivisibly, inseparably; the distinction of natures being by no means taken away by the union but rather the property of each nature being preserved, and concurring in one Person and one Subsistence, not parted or divided into two Persons, but one and the same Son, and only-begotten, God the Word, the Lord Jesus Christ; as the prophets from the beginning [have declared] concerning him, and the Lord Jesus Christ himself has taught us, and the Creed of the holy Fathers has handed down to us."

The same doctrine is set forth in a more condensed form in the second part of the Symbolum Quicunque, or the so-called Athanasian Creed (for text and transl., with notes, cf. Schaff, Creeds, ii. 66-71; see ATHANASIAN CREED).