Leo, bishop, to all monks throughout Palestine.1

Chapter I: The Perverse Misreading of Leo’s Letter to Flavian; the Catholic Faith Condemns Both Nestorius and Eutyches

My solicitude — owed to the universal Church and to all her sons2 — has learned through many reports that some offense has troubled the hearts of your charity. Ignorant or malicious interpreters — it seems — caused you to misunderstand what I preach, unable to translate Latin into Greek aptly or properly. In subtle and difficult matters, even disputants in their own tongue scarcely suffice. Yet this advances my understanding: that, rejecting what Catholic faith condemns, you prefer truth to falsehood — rightly detesting what I too detest from ancient doctrine. Though my letter to Bishop Flavian of blessed memory suffices to manifest itself, needing no purgation or exposition, my other writings accord with it, openly showing my preaching’s meaning. The one, true, singular Catholic faith — to which nothing can be added or subtracted — was assailed by Nestorius before and now by Eutyches: differing in assertion but similar in impiety, each rightly condemned by truth’s disciples for attempting contrary heresies against God’s Church.

Chapter II: Let Nestorius and Eutyches Be Anathematized Together

Let Nestorius be anathematized — who believed the blessed Virgin Mary bore only a man, making the flesh’s person distinct from the divinity’s, not holding one Christ in the Word of God and in the flesh, but preaching separately another son of God and another son of man. Yet with the Word’s immutable essence — coeternal with the Father and the Holy Spirit — the Word became flesh in the Virgin’s womb, so that in one conception and one birth, the same Virgin, through the union of both substances, was both the Lord’s handmaid and His mother; as Elizabeth, according to Luke the Evangelist, understood and declared: Whence is this to me, that the mother of my Lord should come to me? (Luke 1:43). Let Eutyches also be struck by the same anathema — mired in ancient heretics’ errors, choosing the third dogma of Apollinaris, denying the truth of human flesh and soul, asserting one nature for Christ, as if the Word’s divinity were transformed into flesh and soul — ascribing conception, birth, growth, crucifixion, death, burial, resurrection, and ascension solely to the divinity, which accepts none of these without the truth of flesh. If Eutyches rejects Apollinaris’s perversity to avoid deeming the divinity passible, yet dares claim one nature for the incarnate Word, he falls into the madness of the Manichees and Marcion — believing Christ acted in pretense, with no human body but a phantasmal form appearing to the eyes.

Chapter III: Those Who Deny Christ’s Human Nature Have No Part in the Body of the One Whose Truth They Deny

As the Catholic faith has long detested these impious lies — condemned by the concordant sentences of the holy Fathers throughout the world — let those blinded and alienated from the light of truth show why they usurp the Christian name and how they accord with the Gospel, if, through the Virgin’s birth, either flesh without divinity or divinity without flesh arose. It cannot be denied that the Word was made flesh and dwelt among us (John 1:14); nor that God was in Christ, reconciling the world to Himself (2 Cor. 5:19). What reconciliation could have propitiated God to humanity unless the mediator of God and men took humanity’s cause upon Himself? How could He fulfill the mediator’s truth unless He — equal to the Father in the form of God — became our partaker in the servile form, renewing the old man through one new man, breaking the bond of death — contracted through the transgression of one — through the death of the one who alone owed nothing to death?

Chapter IV: Only Those Who Confess the Truth of Christ’s Flesh Are Cleansed by His Blood

The shedding of the just blood for the unjust was so potent in privilege, so rich in price, that if all who were captive believed in their Redeemer, no tyrannical bonds would hold them — as the Apostle says: Where sin abounded, grace did more abound (Rom. 5:20). What hope remains in the aid of this mystery for those who deny the truth of human substance in our Savior’s body? Let them say by what sacrifice they are reconciled, by what blood redeemed — He who gave Himself for us, an oblation and sacrifice to God for a sweet savor (Eph. 5:2). What sacrifice was holier than the true high priest’s offering of His flesh upon the altar of the cross? Though the deaths of many saints were precious in the Lord’s sight (Ps. 116:15), no slaying of an innocent man propitiated the world. The just received crowns — they did not give them; their fortitude brought examples of patience, not gifts of justice. Their deaths were singular: none paid another’s debt — for only our Lord Jesus Christ among all the sons of men was crucified, died, buried, and raised for all.

Chapter V: The Two Natures’ Distinct Properties Demonstrated Through the Works of Christ

In one Lord Jesus Christ — true Son of God and Son of man, one person of Word and flesh — both essences share in the actions; yet the qualities of their works must be understood, discerning by sincere faith what advances the humility of infirmity and what inclines to the height of virtue: what the flesh does not do without the Word, and what the Word does not do without the flesh. Without the Word’s power, the Virgin would not conceive and bear; without the truth of flesh, the swaddled infant would not lie in the manger. Without the Word’s power, the magi would not adore the child declared by a new star; without the truth of flesh, the child would not be ordered to Egypt fleeing Herod’s persecution. Without the Word’s power, the Father’s voice would not say: This is my beloved Son, in whom I am well pleased (Matt. 3:17); without the truth of flesh, John would not proclaim: Behold the Lamb of God, who takes away the sins of the world (John 1:29). Without the Word’s power, no restoration of the weak, no raising of the dead; without the truth of flesh, no food for the hungry and no sleep for the weary. The Lord would not profess equality with the Father without the Word’s power; nor would He say the Father was greater without the truth of flesh. Catholic faith accepts and defends both — believing in one Son of God, man and Word, according to the properties of both divine and human substance.

Chapter VI: Both Natures Unite Unconfused in One Person; Neither Destroys the Other

From the moment the Word became flesh in the Virgin’s womb, no division existed between the divine and human substance — and through all bodily growth, the actions of one person spanned all time. Yet we do not confuse what was inseparably accomplished, but discern by the quality of works what belongs to each form. Neither do divine acts prejudice the human, nor human the divine — both concurring unconfused: neither property consumed, nor person doubled. Let these phantasmal Christians say what substance was fixed to the cross, lay in the tomb, or rose on the third day after the stone of the tomb was rolled away; what body Jesus brought to the sight of His disciples, entering with doors closed and showing the nail marks and the fresh wound of His pierced side to dispel distrust (John 20:20, 27). If heretical obstinacy retains its darkness against the light of truth — let them show what hope of eternal life they claim. It can be attained only through the mediator, the man Christ Jesus: for there is no other name under heaven whereby we must be saved (Acts 4:12); and redemption comes only through His blood, who gave Himself a redemption for all (1 Tim. 2:6).

Chapter VII: Nothing New Was Added to the Son Except the Servile Form; the Exaltation Pertains to What Was Enriched

Though one Lord Jesus Christ — true God and Son of man — is one person of true divinity and humanity, never separable by any division: the exaltation by which God exalted Him and gave a name above every name pertains to the form enriched by such an increase of glorification. In the form of God, the Son was equal to the Father with no distinction in essence or diversity in majesty; the mystery of the Incarnation took nothing from the Word that the Father’s gift restored. The servile form — through which the impassible divinity fulfilled the great mystery of piety — is the human humility raised to the glory of divine power: united from the Virgin’s conception, so that neither did divine acts occur without man nor human acts without God. Thus the Lord of majesty is called crucified, and He who is eternally equal to God is said to be exalted. It matters not which substance names Christ — since with the unity of one person, He is wholly Son of man for His flesh and Son of God for His one divinity with the Father.

Chapter VIII: Leo Laments the Monks’ Violence and Fury Against the Faith’s Defenders

As many heresies — cut from the body of Catholic unity by the holy devotion of presiding Fathers — deserved exile from Christ for making the Incarnation of the Word, the singular salvation of true believers, a stone of stumbling and rock of scandal (1 Pet. 2:8): I marvel that your charity labors to discern the light of truth. As so many manifestations show that the Catholic faith rightly condemned Nestorius, Eutyches, and Dioscorus, no Christian can favor their impiety. Yet I grieve that you oppose evangelical and apostolic doctrine — as I hear — stirring cities with seditions, troubling churches, inflicting injuries and slaughter on presbyters and bishops, forgetting your profession’s purpose in fury and savagery.3 Where is the rule of meekness and peace, the endurance of patience, the foundation of love, the strength of tolerance? What persuasion or persecution led you from Christ’s Gospel — forgetting prophets, apostles, and the saving creed confessed before witnesses at baptism — and yielding to diabolical illusions?

Chapter IX: Leo Calls the Monks to Repentance and the Embrace of the Common Faith

Turn from these diabolical persuasions, sons. No deed violates God’s truth, but truth saves us only in our flesh. Truth, as the prophet says, sprang from the earth (Ps. 85:11) — and the Virgin Mary so conceived the Word, ministering flesh from her own substance, neither adding a person nor voiding a nature. He who was in the form of God took the form of a servant — so that one Christ exists in both: God descending to man’s weakness, man rising to the heights of the divinity. As the Apostle says: Whose are the fathers, and of whom is Christ according to the flesh, who is over all, God blessed forever, Amen (Rom. 9:5).