Ephesus

Oversimplified

• The Third Ecumenical Council (431), which affirmed that Mary is Theotokos ("God-bearer") and condemned Nestorius for dividing Christ into two persons.
• The title defends Christ: if Mary bore God-in-the-flesh, then the child she carried was one person, truly God.

Summary

The Council of Ephesus (AD 431) is the third of the Ecumenical Councils. Nestorius, Patriarch of Constantinople, objected to calling Mary Theotokos ("God-bearer"), preferring Christotokos ("Christ-bearer") — for how could the eternal God be born of a woman? Against him St. Cyril of Alexandria showed that the objection tore Christ in two: a human person born of Mary, only loosely joined to the divine Word.[^1] The Council upheld Theotokos and confessed the one person of Christ in two natures.[^2] Cross-link Theotokos, Nestorianism, The Incarnation.

The title is about Christ, not Mary

"Calling Mary 'Mother of God' sounds like making her divine." The reverse is true — Theotokos is a statement about her Son. The one Mary bore was not a mere man later inhabited by God, but the eternal Word made flesh; and since He is one person, the person born of her is God the Son. To deny her the title is not to protect God's transcendence but to deny that God was truly born, truly one of us. The Church guards Christ's unity through Mary's title. Cross-link Theotokos, Chalcedon.

Nestorius' error

Nestorius so stressed the distinction of the two natures that he ended by splitting the one Christ into two acting subjects — the man Jesus and the divine Word, cooperating rather than united. St. Cyril's answer: there is one Son, one person, who is both God and man; the natures are distinct but never separated into two "someones." Ephesus thus prepared the ground that Chalcedon would complete twenty years later. Cross-link Nestorianism, Constantinople III.

[^1]: St. Cyril of Alexandria, Third Letter to Nestorius and the Twelve Anathemas. [^2]: The Decree of the Council of Ephesus (431).