Council of Chalcedon (451)

The fourth ecumenical council, called by the emperor Marcian and attended by some 520 bishops, which condemned Eutyches and accepted the Tome of Leo. Its definition confesses one Christ in two natures "without confusion, change, division or separation", and names Mary Theotokos "as to his manhood", restating Ephesus in the balance the Church has kept since. The churches that refused it, among them Severus of Antioch's, still shared its faith about Mary. Its own texts are on this site in Henry R. Percival's 1900 translation.