In 451 CE, the Council of Chalcedon issued its “two-natures/one person” definition, which set the boundaries for medieval Christology within the Latin West. The promulgation spoke of .one and the same Christ, Son, Lord, Onlybegotten, recognized in two natures, without confusion, without change, without division, without separation; the distinction of natures being in no way annulled by the union, but rather the characteristics of each nature being preserved and coming together to form one person and subsistence, not as parted or separated into two persons, but one and the same Son and Only-begotten God the Word, Lord Jesus Christ; even as the prophets from the earliest times spoke of him, and our Lord Jesus Christ himself.
