Saints & Angels

Saint Pope Leo the Great: Doctor of the Unity of the Church

Not much is known of the early life of Saint Pope Leo the Great, but it’s more than likely he was born in either Tuscany or Rome. His ordination to the priesthood has no date either. We do know from his writings that he was well educated, but his education did not include Greek. To read some of his writings, please read the complementary post, The Words of Saint Pope Leo the Great.

The first time we really hear from him is when he is a deacon under the Popes – Saint Celestine I and Saint Sixtus III. He was an important deacon since both St. Cyril of Alexandria and Saint John Cassian wrote to him regarding Nestorius and his heresies. He found out that he was elected to the Chair of St. Peter while settling a peace treaty between two imperial generals that broke out in Gaul.

Pope Leo was consecrated to the Papacy on September 29, 440. He displayed phenomenal powers as both a pastor and ruler. At this time in the Church, mainly Bishops did the preaching. He gave great systematic homilies and audiences that gave the people of Rome, and other churches, great hope. We have ninety-six sermons from Leo. They stress the importance of almsgiving and other social teachings of the Christian life.

His doctrinal teachings are magnificent, which focus heavily on the importance of the Incarnation (God becoming Man). He wrote 143 letters and 30 letters were sent to him. This shows how vigilant he was as Supreme Pontiff of the Catholic Church. Pope Leo truly stood as Peter for his declarations as Pope were steeped in authoritative and firm language.

As Pontiff of the Catholic Church, he found himself struggling with issues that arose in the East. In 448, he received a letter from an abbot in Constantinople by the name of Eutyches, who was claiming that the Nestorian heresy (which was condemned by the Council of Ephesus in 431 A.D.) was being revitalized. A year later, another letter was sent to Leo from Eutyches, with duplicates sent to the patriarchs of Alexandria and Jerusalem. He protested to Leo that the Patriarch of Constantinople, St. Flavian, excommunicated him. He wanted to be reinstated. The appeal to be reinstated was supported by Emperor Theodosius II.

Since none of the official proceedings from Constantinople reached Rome, Leo wrote to St. Flavian seeking more information. St. Flavian sent a report from the synod stating that Eutyches was sentenced because he denied the two natures of Jesus Christ.  A kangaroo court known as “The Robber Synod” gathered by Emperor Theodosius was to reinstate Eutyches and to condemn St. Flavian. Many sympathizers and friends of Eutyches attended, including Dioscorus, Patriarch of Alexandria, who presided over the gathering. In the end, Eutyches was reinstated and St. Flavian found himself a condemned man. St. Flavian endured such physical beatings after the synod that he died only a few years later.


After two years had passed, Emperor Marcian gathered a general council. Six hundred Bishops showed up and legates (papal diplomats) represented Pope Leo. This assembly declared Dioscorus excommunicated and vindicated the name of St. Flavian. At the time St. Flavian was still alive (June 13, 449), he received a letter from Pope Leo stating he represented the teachings of the Church that Jesus had two natures with poise and excellence. He also commended him for making known the errors of Nestorianism and Eutychianism. This famous letter has become known as “The Tome of Leo.” It was not read by Dioscorus at “The Robber Synod” but was read by Leo’s legates at the Council of Chalcedon. After hearing this letter written by Leo about the two natures of Christ, the Bishops exclaimed with zeal, “Peter has spoken by Leo!”

Once this ordeal was finally resolved, another issue arose with Attila the Hun in 452 A.D. After sacking Milan and attacking Pavia, he set his army in the direction of Rome. Knowing his role in the sacred office, Pope Leo set out with some of his representatives, government officials, and priests to meet the invaders head on. They came face to face with Attila and his army in the present town of Peschiera. Not wasting anytime, Leo and his clergy interviewed the Hun, persuaded him to leave, and offered him an annual tribute instead of attacking the eternal city. Attila agreed.

Not but three years later, Leo had another invader knocking on the door of the holy city. This time, the Vandal, Genseric, came upon the nearly defenseless walls of Rome. Unfortunately, Leo was not as successful this time in persuading the invaders. They did not kill and slaughter as they had done in other places, but after 15 days, they took many treasures and captives back to Africa with them.

Immediately, Pope Leo first set out to repair the damages and evils the Vandals had performed. Second, he sent priests with alms to minister to those who were taken to Africa. Third, he replenished, as much as he could, the sacred vessels and art that was stolen by the invaders.

In twenty-one years as Supreme Pontiff of the Catholic Church, he trusted in God and never lost hope, even in the most tragic times. He is an example of a strong Pope who did not get ruffled at the evils he faced in his holy and sacred position as Vicar of Christ. Many people adored him and he gained the admiration of both the rich and the poor. Leaders and barbarians respected him and his priests and the lay faithful loved him.

Pope St. Leo the Great entered eternal glory on November 10, 461. His body is preserved in Saint Peter’s Basilica. He was canonized a saint before the Congregation for Saints was formalized. Pope Benedict XIV declared him a Doctor of the Church on October 15, 1754. He is one of only a few that carries the title, “Great.”


Walsh, Michael. Butler’s Lives of the Saints. HarperSanFrancisco, 1991.

4 replies »

  1. Thank you for the excellent info on Pope St. Leo! I couldn’t help but compare his pontificate to another that one day might be called “the great,” namely, Blessed John Paul II. Their pontificates were similar in length (Leo 21 yrs; JP II 25 yrs). They were both dealing with monumental heresies in their day . . .Leo (Nestorianism and Eutychianism) and JP II (Modernism and Postmodernism). In fact, St. John Bosco’s dream which shows the Pontiff dressed in white securing the bark of Peter safely to the shore by the pillars of the Eucharist and Mary while “books” are being hurled at it all the while, is fulfilled in JP II’s pontificate. Interestingly, his last two encyclicals were on Mary and the Eucharist!!


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