In A.D. 381 the Council of Constantinople rejected the teaching of an elderly bishop from Syria, named Apollinaris. Apollinaris had theorized that Jesus Christ’s divine nature displaced Jesus’ human mind and will. To him, Jesus possessed only a divine nature, and therefore did not truly take on the fallen nature of humanity.
Controversy about the relationship between the divine and human natures of Jesus continued with Nestorius of Antioch, who was appointed bishop of Constantinople in 428. Nestorius concluded that Jesus had two separate natures and two wills, making him two persons— a double being — one divine and the other human, sharing one body. Nestorius’ teaching was condemned by a church council at Ephesus in 431, but the controversy did not end.
In the 440s, a respected monk from Constantinople, Eutyches, denied that Jesus was truly human. He taught that Jesus did not exist in two natures because his human nature was absorbed or swallowed up by his divine nature. Flavian, bishop of Constantinople, convened a synod in 448, condemning Eutyches’ position, but Eutyches appealed the decision. The fight took a nasty turn when Dioscorus, Patriarch of Alexandria, became determined to reinstate Eutyches and his views. Eastern emperor Theodosius II, also favoring Eutyches’ position, called another church-wide council to meet at Ephesus in August 449. He appointed Dioscorus to chair the proceedings and to silence any dissent.
Leo I, bishop of Rome, sent delegates to the synod with his Tome, an exposition of how the two natures, divine and human, are joined in Christ. Dioscorus prevented the reading of Leo’s letter and rejected his position. Eutyches’ teaching was declared orthodox. Bishops who refused to accept the council’s decision were deposed.
Council of Chalcedon
An unexpected event dramatically changed the situation. On July 28, 450, while out riding, Theodosius’ horse bolted. The emperor fell, broke his neck and died. His sister Pulcheria became empress with her husband, Marcian, as co-emperor. They were opposed to Eutyches’ teaching and eager to redress the wrongs perpetrated by Dioscorus.
Emperor Marcian called for a church council to meet at Chalcedon, on the outskirts of Constantinople. More than 500 bishops attended — the largest church council gathering to that time. All delegates were from the Eastern Church, except the few representatives from Rome and two from Africa. Deliberations lasted from October 8 to November 1, 451.
Leo again sent representatives with his Tome, which was read and approved by the council. Chalcedon reversed the “Robbers’ Council” decision and condemned Eutyches’ teaching. It anathematized those who taught that Christ had only a single, divine nature and those “who imagine a mixture or confusion between the two natures of Christ.”
Definition of Faith
Marcian urged the council to write a statement of faith to provide unity and understanding for the Church. In response, the council produced the “Chalcedonian Definition.” The Definition affirms that Christ is “complete in Godhead and complete in humanness, truly God and truly human.” He is “of one substance (homoousios) with the Father as regards his Godhead, and at the same time of one substance with us as regards his humanity.”
Jesus Christ is to be “recognized in two natures, without confusion, without change, without division, without separation.” The “distinction of natures” is “in no way annulled by the union.” “The characteristics of each nature” are to be considered as “preserved and coming together to form one person and subsistence.” They are not to be “separated into two persons.”
In summary, the Definition confesses Jesus Christ is “one person, who is both divine and human.” Though its wording has been criticized as inadequate, it has helped the church in “setting the limits beyond which error lies” in speaking of the human and divine union in Christ. The Definition confesses the gospel message that Jesus Christ assumed our fallen humanity in order to save us, for as Gregory of Nazianzus (329-389), said, “That which he [Christ] has not assumed he has not healed; but that which is united to his Godhead is also saved.”