St. Cyril of Alexandria was at the center of one of the great dramas in Christian theology, and it is thanks to his courage and clear vision that our beliefs about Jesus have been faithfully passed on to us.

He was born in Alexandria, Egypt, in the late 300s. His uncle led the Church in Alexandria, and when he died, Cyril was named bishop there. Cyril was known as a vigilant defender of the faith, and kept careful watch over the Christian communities that were under his supervision.

In 428 a monk and priest named Nestorius was named archbishop of Constantinople, a city that was the seat of the empire. Nestorius began proclaiming beliefs about Jesus that claimed he was really two persons—divine and human—and that the divine person of Jesus simply inhabited the human part of him. In short, he was teaching that Jesus was God who walked on earth wearing a human body like a suit. As a consequence, he said, Mary should not be called Mother of God, but only mother of the man, Jesus.

Cyril objected and raised the matter with the pope. The pope called a meeting in Rome to examine the claims and sided with Cyril, and had Cyril deliver the verdict to Nestorius, who was to be excommunicated unless he retracted his claims. Nestorius refused.

In 431 a large council was gathered at Ephesus to decide the matter once and for all—Cyril led the council and acted as the pope’s representative. Nestorius was in town, but refused to attend. In his absence, the council condemned his works and excommunicated him.

The story does not end there. A group of some 40 bishops from Antioch arrived to the council late, and supported Nestorius. They were not accepted to the council, so they formed their own council in town and claimed to depose Cyril.

Both sides appealed to the emperor. Confused, the emperor had both Cyril and Nestorius jailed until it could all be sorted out.

Finally, representatives from the pope arrived and explained the matter to the emperor, and Cyril was released and restored to honor. Nestorius was sent back to Antioch to retire to his monastery, and he was later further exiled to the desert. The group of bishops from Antioch reconciled with Cyril and gave a statement of their orthodoxy.

Until he died in 444, Cyril maintained the faith that was handed to him from the apostles. Even his contemporaries knew him to be a great defender of the faith. Because of his strong and clear leadership, the declarations of the Council of Ephesus continue to guide our faith today. Thanks to Cyril’s leadership, we understand Jesus’ Incarnation to mean that Jesus was fully God and fully man—one person with two natures.

This may seem like a semantic abstraction, but the implications are tremendous for Christian spirituality. In the Incarnation, God fully joined our humanity in the person of Jesus. This was not God paying us a visit or pretending to be human for a while—God became human in every way except for sin. This means that every part of our humanity has the potential to connect us with the divine—we can find God in beauty and goodness, in relationships and learning truth, for example. Even our daily experience—the mundane progression of our days—can be a source of connection to the divine for us.

St. Cyril of Alexandria has been named a doctor of the Church, a title given to 37 saints who are known for elucidating the faith by their words or example—he is known as the Doctor of the Incarnation. His relics rest in the reliquary chapel in the Basilica, and his image is used here with permission from Catholic.org.

St. Cyril of Alexandria, you guided the Church through heresy and handed us the faith we live today—pray for us!