Chapter 16: On the canons of the councils

5. Among the rest of the councils we know there are four venerable synods which embrace the whole faith in its chief heads, like the four Gospels or the four rivers of Paradise.

6. Of these the first, the Nicene synod of 318 bishops, was held when Constantine was emperor. In it the blasphemy of the Arian perfidy was condemned, which the same Arius gave utterance to concerning the inequality of the holy Trinity. The same holy synod in the creed defined God the son as consubstantial with God, the father.

7. The second synod of 150 fathers gathered at Constantinople under Theodosius the elder, and condemning Macedonius, who denied that the Holy Spirit was God, proved that the Holy Spirit was consubstantial with the Father and the Son, giving the form of the creed which the whole confession, Greek and Latin, preaches in the churches.

8. The third synod, the first of Ephesus, of 200 bishops, was held under Theodosius II, and it condemned with a just anathema Nestorius, who asserted that there were two persons in Christ, and showed that the one person of the Lord Jesus Christ was immanent in the two natures.

9. The fourth synod of 630 priests was held at Chalcedon under Martianus, and it condemned by the unanimous vote of the fathers Euthyches, abbot of Constantinople, who asserted that the nature of the Word of God and of flesh was one, and his defender, Dioscorus, bishop of Alexandria, and Nestorius himself a second time, along with the remaining heretics, the same synod stating that Christ the Lord was so born of the virgin that we confess in him the substance both of the divine and of the human nature.

These four are the principal synods, stating most fully the doctrine of faith; and whatever councils there are which the holy Fathers, full of the spirit of God, have ratified, after the authority of these four, they continue established in all strength.