Acta Sanctorum: Pope St. Leo the Great (Nov 10)
November 10, 2026
Fr. John Colacino C.PP.S.

 

 

November 10
 
Pope St. Leo the Great
 

Life (400?-461)

The designation “great”, applied to a ruler, is very rare. A ruler does not assume that title himself (or herself); it is bestowed by posterity on those who have discharged their tasks with extraordinary ability. History has attached the adjective to only three popes. The first of them was St. Leo I, Father and Doctor of the Church.

Leo’s early background is obscure. When we first encounter him as a cleric of the papal court in the early fifth century, he is already an influential theologian, administrator and diplomat. In the year 440 Leo was sent to Gaul by Pope Sixtus III to reconcile two Roman generals. While he was on this mission Sixtus died, and Leo was elected to succeed him.

It soon became clear that Pope Leo was a man of principle and a man of decision. Italy looked to him as its special protector. In those days Europe was being overrun by barbarian tribes, and the Roman imperial officials were unable to offer strong military resistance. Thus Attila and his Huns swept through northern Italy in 452, and having laid waste to Milan and Pavia, turned towards Rome. Emperor Valentinian III and the Roman Senate commissioned the pope as the man best fitted to negotiate with this enemy before he reached the Capital. Leo did so, and was able to deter Attila from attacking Rome by an agreement to pay him a yearly sum of tribute.

Pope Leo was not so successful in 455 when Gaiseric, leader of the barbarian Vandals, turned up at the gates of Rome eager for booty. The pope was able, however, to persuade Gaiseric to be content with pillaging the city, without slaying its citizens or burning its buildings. Leo followed through, nonetheless. He quickly sent priests to Africa to minister to the many Christian prisoners that the Vandals had captured, and he began at once to replace the sacred vessels and ornaments that the invaders had stolen from Rome’s churches.

In dealing with church administration, Pope Leo was firm and decisive: he had the duty to supervise all the churches, East and West. (In fact, it was Leo the Great who first developed clearly the theology of the primacy that the bishops of Rome exercise throughout Christianity.)

What Leo became most famous for was his response to the current heresies concerning the Incarnation. In his day the Eastern heretic Nestorius defended the error that Christ, in the Incarnation, was actually two persons - one human, one divine. Nestorius’ opponent Eutyches argued just the opposite error; he claimed that after the Incarnation Christ was not only one person, but had only one nature. Both of these errors implied that Jesus was not the God man. If this were true, His death on the cross as man, offered up by Him as God, could not have won our redemption. Leo responded with beautiful clarity, that Christ is one person with two natures, that of God and that of man. Not only was He “one in substance” with the Father as God, but also “one in substance” with the human race through His Mother Mary.

When the ecumenical council of Chalcedon met to reject these errors in A.D. 451, they adopted Pope Leo’s dogmatic letter declaring Christ to be both true God and true man. In fact, the Fathers of the council hailed the pope’s clarification, crying out, “Peter has spoken by Leo!” If this energetic pope won the admiration of all, it was because of his serene faith that the Holy Spirit would never fail the Church, Christ’s body. A point that St. Leo always emphasized in his beautiful sermons was that every Christian has been joined by baptism to Christ, the head of His body, the Church, and by that fact has been made a sharer in His divinity. “O Christian,” the pope cried out, “acknowledge your worth! Recall that you have been rescued from the power of darkness and have been transferred into the light and kingdom of God.” Sublime words from this holy and wise successor of the prince of the apostles!  --Father Robert F. McNamara

Scripture (Sirach 39:6-11)

If it pleases the Lord Almighty,
  he who studies the law of the Most High
  will be filled with the spirit of understanding;
He will pour forth his words of wisdom
  and in prayer give thanks to the Lord,
Who will direct his knowledge and his counsel,
  as he meditates upon his mysteries.
He will show the wisdom of what he has learned
  and glory in the law of the Lord’s covenant.
Many will praise his understanding;
  his fame can never be effaced;
Unfading will be his memory,
  through all generations his name will live;
Peoples will speak of his wisdom,
  and in assembly sing his praises.
 
Writings
 
(Year. A). Narrow and difficult is the way that leads to life. No one would set foot upon it, no one would advance one step, if Christ himself had not opened the difficult entrance by making himself the way. So it is that he who bids us make the journey also enables us to do so; he both persuades us to undertake the labour and leads us to our rest. We make a vain pretence if we fail to follow the teaching of him in whose name we glory, teaching which would not be burdensome and would free us from all perils if only we loved nothing but what he commanded us to love. For there are two kinds of love from which proceed all desires, and they are as different in nature as they are in origin: the rational mind, which cannot exist without love, loves either God or the world. In the love of God there can be no excess, but the love of the world is harmful in every way. We must therefore cling inseparably to the good things that are eternal but, like passers-by, make use of those that are temporal; then, as pilgrims hastening to our homeland, we shall use any worldly good fortune that comes to us as a means to further our journey, not as an enticement to detain us. The time is short. From now on those who have wives should live as though they had none; and those who mourn as though they were not mourning; and those who rejoice as though they were not rejoicing; those who buy should live as though they had no possessions, and those who have to deal with this world as though they had no dealings with it. For the form of this world is passing away. But because the world attracts us by its beauty, abundance, and variety, it is not easy to turn away from it unless, in the beauty of visible things, one loves the Creator rather than the creature; for when the Creator says: You shall love the Lord your God with all your heart and with all your mind and with all your strength, he shows that it is not his will that we should loosen the bonds of our love for him in any respect whatever. And by joining to this precept love of our neighbour, he commands us to imitate his own goodness, loving what he loves and doing what he does. It is true that we are God’s field, God’s building, and neither is the one who plants of any importance, nor the one who waters, but God who makes things grow. Nevertheless, in all his work he requires our ministry and service, and desires us to be the stewards of his gifts, so that those who bear God's image may do his will. This is why in the Lord’s prayer we say with great devotion: Thy kingdom come, thy will be done on earth as it is in heaven. What do we ask for in these words but that God should subject to himself those who are not yet subject to him, and that he should make men ministers of his will upon earth, as he does his angels in heaven? In making this petition we show that we love God and also our neighbour; our love is one and undivided, since our desire is that the servant should serve, and the Master command. (Sermons) 
 
Musical Selection (Palestrina)
 
 

Tu es Petrus, 
et super hanc petram aedificabo ecclesiam meam
et portae inferi non praevalebunt adversus eam.
Et tibi dabo claves regni caelorum.

Quodcumque ligaveris super terram, erit ligatum et in caelis,
et quodcumque solveris super terram, erit solutum et in caelis.
Et tibi dabo claves regni caelorum.

You are Peter,  And upon this Rock I will build My Church: and the gates of hell shall not overcome it.
And I will give you the keys to the kingdom of heaven.

Whatever you bind upon earth shall be bound in heaven,
and whatever you release upon earth shall be released in heaven,
and I will give you the keys to the kingdom of Heaven.

Collect

God our Father, 
who made your servant Leo strong in the defence of the faith: 
fill your Church with the spirit of truth that, 
guided by humility and governed by love, 
she may prevail against the powers of evil; 
through Jesus Christ your Son our Lord, 
who lives and reigns with you, 
in the unity of the Holy Spirit, 
God, now and for ever. Amen. (English Missal)

 

Archives