Pope Leo the Great
Eastern emperor Theodosius II
Eastern emperor Marcian
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. 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:
When the emperor died, Marcian became emperor and opposed Eutyches’ teaching. Emperor Marcian called for a church council to meet at Chalcedon, on the outskirts of Constantinople. 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.”
1.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.”
2.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.”