[1] Chalcedonian Christianity accepts the Christological Definition of Chalcedon, a Christian doctrine concerning the union of two natures (divine and human) in one hypostasis of Jesus Christ, who is thus acknowledged as a single person (prosopon).
[4][5] Chalcedonian Christology is upheld by Catholicism, Eastern Orthodoxy, and some branches of Protestantism, and thus comprises the majority of Christianity.
Those present at the council also rejected the Christological doctrines of the Nestorians, Eutychians, and Monophysites.
The Hypostatic Union was also viewed as one nature in Roman Christianity by a minority around this time.
[11] Single-nature ideas such as Apollinarism and Eutychianism were taught to explain some of the seeming contradictions in Chalcedonian Christianity.