MONOPHYSITISM, meaning "one nature" and referring to the person of Jesus Christ, is the name given to the rift that gradually developed in Eastern Christendom after the Council of Chalcedon in 451. While the definition agreed upon at the council laid down that Christ should be acknowledged "in two natures," human and divine, the properties of each nature retaining their identity, the Monophysites held that after the incarnation the two natures became one, so that all the thoughts and acts of the Savior were those of a single unitary being, God in Christ.

The germ of Monophysitism may be found in the logos-sarx (Word-flesh) theology of the Alexandrian church. The question of how Christ's personality should be acknowledged could not be avoided, however, once the Creed of Nicaea (325) confessed that he was "of one substance with the Father." If this was so, how was Christ to be considered of...