Washington, D.C. Newsroom, Nov 10, 2023 / 12:00 pm (CNA).
Throughout the last two millennia, the Catholic Church has only granted the title “doctor of the Church” to 37 saints, one of whom we celebrate today on Nov. 10: St. Leo the Great, the 45th bishop of Rome.
Pope Leo I, who was the first pope to be remembered posthumously as “the great,” began his papacy in 440 and served until his death in 461. During his pontificate, he worked to clarify doctrines related to Christ’s human and divine natures.
The pontiff was a “pope-theologian, but he’s also known as a remarkable bishop,” Thomas Clemmons, a professor of Church history at The Catholic University of America, told CNA, adding that “theologian popes are rare.”
St. Leo’s papacy began nine years after the Council of Ephesus, which condemned Nestorius and the heresy of Nestorianism, leading many of Nestorius’ followers to schism. The heresy rejected the close union of Christ’s human and divine natures and rejected the Marian title of “Theotokos,” or God-bearer, claiming that Mary only gave birth to Christ’s human nature.
Rising out of the Nestorian schism were more Christological conflicts over the relationship between Christ’s humanity and divinity. Eutyches, an opponent of Nestorius, went too far in the opposite direction, claiming that Christ’s human and divine natures were fused into one single nature. His human nature, Eutyches claimed, was “dissolved like a drop of honey in the sea.”
This heretical understanding, according to Clemmons, turned Christ into a “third thing” or a “kind of monster” rather than the Catholic understanding of Christ as “one Person” with “complete and true humanity and complete and true divinity.”
To combat Eutyches’ error, Pope Leo wrote a letter to Flavian I, the archbishop of Constantinople, which clarified the hypostatic union of Christ’s distinct human nature and distinct divine nature. The letter, which became known as “Leo’s Tome,” is the pontiff’s most famous work and set the stage for defining Christological doctrines at the Council of Chalcedon in 451.
“Both natures retain their own proper character without loss: and as the form of God did not do away with the form of a slave, so the form of a slave did not impair the form of God,” Pope Leo wrote in the letter.
“From the mother of the Lord was received nature, not faultiness: nor in the Lord Jesus Christ, born of the Virgin’s womb, does the wonderfulness of his birth make his nature unlike ours,” the letter continued. “For he who is true God is also true man: and in this union there is no lie, since the humility of manhood and the loftiness of the Godhead both meet there.”
In emphasizing the fullness of Christ’s human nature in the letter, Leo cites the genealogy of Christ listed in the Scripture, along with his human experiences, particularly suffering and death on the cross: “Let [Eutyches] not disbelieve [Christ is a] man with a body like ours, since he acknowledges [Christ] to have been able to suffer: seeing that the denial of his true flesh is also the denial of his bodily suffering.”
Leo emphasized the words of the Creed when emphasizing the fullness of Christ’s divine nature, stating: “Not only is God believed to be both Almighty and the Father, but the Son is shown to be co-eternal with him, differing in nothing from the Father because he is God from God, Almighty from Almighty, and being born from the Eternal One is co-eternal with him.”
The pontiff bolstered his argument with citations from Scripture that point to the fullness of Christ’s divine nature and the fullness of his human nature.
“To be hungry and thirsty, to be weary, and to sleep, is clearly human,” Leo said. “But to satisfy 5,000 men with five loaves, and to bestow on the woman of Samaria living water, droughts of which can secure the drinker from thirsting any more, to walk upon the surface of the sea with feet that do not sink, and to quell the risings of the waves by rebuking the winds, is, without any doubt, divine.”
Clemmons praised Leo’s Tome as a “simple and clear text” that is “very readable and very instructional now,” even more than 1,500 years later.
At the time, however, the letter was met with hostility from supporters of Eutyches’ position in Constantinople: “[It was] sent there, read aloud, and they rejected it,” Clemmons said. Emperor Theodosius II convened the faux Second Council of Ephesus in 449, which rejected St. Leo’s letter and defended Eutyches. The supporters of Eutyches brutally assaulted Archbishop Flavian I for defending St. Leo’s position, deposed him, and sent him into exile. He died from his injuries.
St. Leo referred to the council as the “Latrocinium,” the “robber council,” and in 451 the Church convoked the Council of Chalcedon, which defined clearly the hypostatic union of Christ’s human and divine natures and rejected the Second Council of Ephesus.
Chalcedon Council documents cite Leo’s letter and affirm his teachings on the two natures of Christ, stating that Christ “must be confessed to be in two natures, unconfusedly, immutably, indivisibly, inseparably [united] … without the distinction of natures being taken away by such union.”
When speaking to a general audience in 2008, Pope Benedict XVI referred to St. Leo the Great as one of the greatest popes in the history of the Church.
“As the nickname soon attributed to him by tradition suggests, he was truly one of the greatest pontiffs to have honored the Roman See and made a very important contribution to strengthening its authority and prestige,” Benedict said.
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A question arises in this article that deserves attention for sake of clarification of a significant truth in respect to the Incarnation of Christ in the womb of the Blessed Virgin. A nuance of meaning that was lost but identified by Cyril of Alexandria and verified by Thomas Aquinas.
Placed in its historical perspective prior to his elevation to the papacy, Leo the Great was a deacon named Giovanni di Lorenzo de Medici from Florence, Italy. A contemporary and assistant to Cyril, the patriarch of Alexandria on the issue of the hypostatic union. Hypostasis in Gk meant a substance to which all qualities of a being or person belonged. A term interchangeable with suppositum.
“The Mode of Union in the Divine Word. Summa Theologiae Part 3 Question 2. Objection 1. It would seem that the union of the Word Incarnate did not take place in the suppositum or hypostasis. For Augustine says [Enchiridion xxxv, xxxviii]: ‘Both the Divine and human substance are one Son of God, but they are one thing [aliud] by reason of the Word and another thing [aliud] by reason of the man’. And Pope Leo says in his letter to Flavian [Ep. xxviii]: ‘One of these is glorious with miracles, the other succumbs under injuries’. But ‘one’ [aliud] and ‘the other’ [aliud] differ in suppositum. Therefore the union of the Word Incarnate did not take place in the suppositum.
On the contrary, Damascene says [De Fide Orth. iii, 3,4,5]: ‘In our Lord Jesus Christ we acknowledge two natures and one hypostasis’.
I answer that, Some who did not know the relation of hypostasis to person, although granting that there is but one person in Christ, held, nevertheless, that there is one hypostasis of God and another of man, and hence that the union took place in the person and not in the hypostasis. Now this, for three reasons, is clearly erroneous. First, because person only adds to hypostasis a determinate nature, viz. rational, according to what Boethius says [De Duab. Nat.], ‘a person is an individual substance of rational nature’; and hence it is the same to attribute to the human nature in Christ a proper hypostasis and a proper person. And the holy Fathers, seeing this, condemned both in the Fifth Council held at Constantinople, saying: ‘If anyone seeks to introduce into the mystery of Incarnation two subsistences or two persons, let him be anathema. For by the incarnation of one of the Holy Trinity, God the Word, the Holy Trinity received no augment of person or subsistence’. Now ‘subsistence’ is the same as the subsisting thing, which is proper to hypostasis, as is plain from Boethius [De Duab. Nat” (ST 3a Q 2).
The significance of the ‘nuance’ in meaning is that it confirms the hypostatic union occurred within the womb of the Virgin Mary, as one person possessing a human and a divine nature with no allusion to a preexisting person. That is why Cyril of Alexandria issued his anathema contra Nestorius, patriarch of Constantinople, who implied the preexistence of the second divine person of the trinity. Nestorius’ error was condemned in Rome 430 by pope Celestine and subsequently at Ephesus 431 where Cyril submitted his twelve anathemas against Nestorius. Although it may be argued that Cyril exaggerated his allegations against Nestorius it nevertheless clarified without ambiguity the incarnation of Christ the second, one complete person of the trinity in the womb of the Blessed Virgin Mary.
By ‘preexistence of the second divine person of the trinity’ I mean to say that the incarnate divine Word, the same Word who existed from all eternity was incarnate in the womb of the Blessed Virgin. That the Word was not a separate preexisting entity existing apart from the person conceived in Mary’s womb. The latter presumption led many in the Eastern tradition to consider Christ a human person with a special, ancillary relationship with the divine Word. This is what the Fathers condemned at the 5th Council at Constantinople 553 held under the auspices of emperor Justinian, who himself professed his belief in the two natures of the one person Christ. Greek Orthodoxy holds to this doctrine although they maintain Christ has one will, the divine. And also the Filioque clause issue which the Latin Church holds that the Holy Spirit issues from both Father and Son. These differences in Gk Orthodoxy from Roman Catholicism indicate the lingering influence Arianism had in the East.
Correction: Pope Leo the Great was not born with the name Giovanni di Lorenzo de Medici. Should have known [the Medici’s were much later, prominent during the Renaissance] but I was roped in.