The Horos of the Council of Chalcedon (AD 451)

Following the Holy Fathers we teach with one voice that the Son of God and our Lord Jesus Christ is to be confessed as one and the same person, that He is perfect in Godhead and perfect in manhood, very God and very man, of a reasonable soul and human body consisting, consubstantial (homoousios) with the Father as touching His Godhead, and consubstantial (homoousios) with us as touching His manhood; made in all things like unto us, sin only excepted; begotten of His Father before the ages (æons) according to His Godhead; but in these last days for us men and for our salvation born into the world of Mary, the Virgin Mother of God (Theotokos), according to His manhood.

This one and the same Jesus Christ, the only-begotten Son of God must be confessed to be in two natures, unconfusedly, immutably, indivisibly, inseparably united, and that without the distinction of natures being taken away by such union, but rather the peculiar property of each nature being preserved and being united in one person (prosopon) and one subsistence (hypostasis), not separated or divided into two persons (prosopa), but one and the same Son and only-begotten, God the Word, our Lord Jesus Christ, as the Prophets of old time have spoken concerning Him, and as the Lord Jesus Christ hath taught us, and as the Creed of the Fathers hath delivered to us.