ENCYCLICAL OF POPE PIUS XII
ON THE COUNCIL OF CHALCEDON
TO THE VENERABLE BRETHREN, THE PATRIARCHS, PRIMATES, ARCHBISHOPS, BISHIOPS, AND OTHER ORDINARIES IN PEACE AND COMMUNION WITH THE APOSTOLIC SEE 
1. Christ, the Eternal King, before he promised the headship of the Church to Peter, the son of John, called together his disciples, and asking them what they and other men believed about himself, praised the faith which would conquer all the storms and attacks of the evil powers, and which Peter, enlightened by the Eternal Father, had declared in these words: 'Thou art Christ, the Son of the Living God' (Matt. xvi, 16). It is this faith which is 'the strength of God for the salvation of every believer' (Rom. i, 16), and which brings forth the apostle's crown, the martyr's palm and the virgin's lily. This faith has been defended and lucidly clarified especially by three oecumenical councils, those of Nicea, Ephesus and Chalcedon. It is now fifteen hundred years since the last of these was concluded. It is fitting, therefore, that both at Rome and in the whole Catholic world, this most happy event should be celebrated with due solemnity; and so giving thanks to God the inspirer of all holy counsels, with deeply moved hearts, we institute those solemnities.
2. As our predecessor Pope Pius XI of happy memory solemnly commemorated the Nicene council in 1925 in the sacred city, and by his encyclical letter Lux Veritatis recalled the sacred council of Ephesus in 1931, so we by the present letter pay a tribute of equal honor to the council of Chalcedon. For inasmuch as both councils, Ephesus and Chalcedon, were concerned with the hypostatic union of the Incarnate Word, they are intimately connected with one another. From the earliest times both councils have enjoyed the highest honor, equally in the East, where they are celebrated in the liturgy, and in the West. St. Gregory the Great bears witness in the West to this fact when he praises both councils together with two of the preceding century, namely, those of Nicea and Constantinople, in the memorable sentence: - 'On them, as a four-cornered stone, the building of the holy faith stands erect, and whoever does not hold their firm doctrine, whatever may be his life or activity, even if he seems to be a rock, nevertheless lies outside the building' (Regist. Epist. i, 25 . Pl. lxxvii, 478, ed. Ewald i, 36).
3. From the consideration of this event and its attendant circumstances, two points arise and stand out, and these we wish, as far as possible, to make yet more clear. They are: the primacy of the Roman pontiff which shone forth clearly in this very grave christological controversy and, secondly, the great importance and weight of the dogmatic definition of Chalcedon. Let those who, through the evils of the time, are separated from the bosom and unity of the Church, especially those who dwell in Eastern lands, not delay to follow the example and the customs of their ancestors in paying due respect to the Roman primacy. And let those who are involved in the errors of Nestorius or Eutyches penetrate with clearer insight into the mystery of Christ and at last accept this definition in its completeness. Those, also, who are led by an excessive desire for new things and, in their investigation of the mystery of our redemption boldly dare to go beyond the sacred and inviolable limits [of true doctrine], should ponder this definition more truly and more deeply. Finally, let all those who bear the Catholic name draw from it strong encouragement; let them hold fast this evangelical pearl of great price; let them profess and hold it with unadulterated faith; let them render it due honor inwardly and outwardly; and - what is still more important - let them pay it the tribute of lives in which, through God's mercy, they shun whatever is unworthy, incongruous or blameable, and in which they shine with the beauty of virtue, so that they may become sharers of this divinity, who deigned to be a partaker of our humanity.
4. Now, to treat of things in due order, let us recall from the beginning the events which we commemorate. The originator of the whole controversy under discussion at Chalcedon was Eutyches, a priest and archimandrite in a famous monastery of Constantinople. This man, in refuting the Nestorian heresy which maintained that there were two persons in Christ, fell into the opposite error.
5. 'A rash man and quite unskilled' (St. Leo the Great to Flavian, Ep. xxviii, I. Pl. liv, 755 s.), with an extremely obstinate disposition, Eutyches asserted that two moments of time should be distinguished: thus before the Incarnation there were two natures in Christ, the human and the divine; after their union, however, only one existed, since the Word had absorbed the human nature (hominem); the body of the Lord came from the Virgin Mary, but was not of our substance and matter; if, indeed, it was human, it was not consubstantial with us, nor with her who gave birth to Christ according to the flesh (cf. Flavian to St. Leo, Ep. xxvi; Pl. liv, 745). Therefore, it was not in true human nature that Christ was born, suffered, was fastened to the cross and rose from the tomb.
6. Eutyches did not grasp that before the union the human nature of Christ did not exist at all, for it only began at the time of his conception; and it is absurd to suppose that after the union one nature resulted from the coalescence of two; for there is no way in which two true and distinct natures can be reduced to one, and the more so [in this case] since the divine nature is infinite and unchangeable.
7. Whoever judges wisely of these opinions will quickly conclude that by them the mystery of the divine dispensation is dissipated into shadowy absurdities and riddles. It was quite clear to those who were of sound piety and theology that this absurd novelty, so repugnant to the teachings of the prophets, to the words of the Gospel and to the dogma contained in the Apostles' Creed and the Nicene profession of faith, had been taken from the vaults of Apollinaris and Valentine.
8. A special synod was called at Constantinople; St. Flavian, bishop of that city, presided; Eutyches, who had been vigorously spreading his errors throughout the monasteries, was accused of heresy by Bishop Eusebius of Dorylaeum, and condemned. He considered that an injury had been done to him who had withstood the growth of the Nestorian heresy, and appealed to the judgment of some of the bishops placed in higher authority. And so St. Leo the Great, bishop of the Apostolic See, also received letters of appeal of this kind. No one could have been more suitable and capable for the refutation of Eutyches's error. His solid and shining virtues, his zealous watch equally over peace and religion, his strenuous defense of the dignity of the Roman see, his skill in the spoken word and equally in the management of affairs, have won for him the admiration of all succeeding ages. Moreover, he was accustomed in his allocutions and letters to maintain with great piety and pious greatness that the mystery of the one person and the two natures in Christ could never be preached sufficiently. 'The Catholic Church lives by this faith, and is nourished by it, that in Jesus Christ neither is the humanity believed with the true Divinity, nor the divinity without true humanity' (St. Leo the Great, Ep. xxviii, 5. PL. liv, 777).
9. The Archimandrite Eutyches, however, was not confident of the patronage of the Roman pontiff So he craftily made use of his friend Chrysaphius, who was a favorite of the emperor, to persuade Theodosius II to take his part and to summon another council at Ephesus under the presidency of Dioscorus, bishop of Alexandria. This man, who as both a friend to himself and an enemy to Flavian, bishop of Constantinople, deceived by a similarity of terms, gave it out that, like his predecessor Cyril, he was determined to defend with all his power that, as there was one person in Christ, so after the 'unification', there was also one nature in Christ. For the sake of peace St. Leo the Great sent delegates to the council. Among other letters, they brought to the council two epistles, one addressed to the synod, and the other containing a perfect and full developed doctrine in which the errors of Eutyches were refuted, addressed to Flavian.
10. But at this synod of Ephesus, which St. Leo rightly called a 'Robbers' council', Dioscorus and Eutyches carried off everything with a high hand. The first places in the council were denied to the apostolic delegates; the letters of the pope were not allowed to be read, the votes of the bishops were extorted by threats and stratagems; among others Flavian was accused of heresy, deprived of his pastoral ministry and thrown into prison, where he died. The rash fury of Dioscorus even went to the length of criminally hurling an excommunication at the Apostolic See itself. As soon as St. Leo learnt from the deacon Hilary of the evil deeds of this council, he condemned and annulled all the decrees and decisions made by it. His grief at these crimes was greatly increased by the frequent appeals to his authority made by the numerous bishops who had been deposed.
11. Worthy of mention are the lines written by Flavian and by Theodoret of Cyrus to the chief pastor of the Church. These are Flavian's words: 'After the unjust sentence which it pleased Dioscorus to pronounce against me, everything, as if by some prearranged pact, turned against me; when I appealed to the throne of the prince of the apostles, the Apostolic See, and to the holy synod which is under the authority of your Holiness, a large number of soldiers surrounded me, prevented my taking refuge at the altar, and tried to drag me from the church' (Schwartz. Acta Concil. OEcum. II Vol. II, pars prior, p. 78). Theodoret wrote as follows: 'If Paul, the preacher of truth . . . betook himself to the great Peter, much more do we who are weak and lowly turn to the Apostolic See, that we may obtain from you a remedy for the ulcers of the Church. For it is your part to direct us in all things. I await the decision of the Apostolic See . . . above all that I may learn whether I ought to accept this unjust decision or not: for it is your decision that I await' (Theodoret to Leo the Great, Ep. lii, 1, 5, 6. PL. liv, 847 and 851, cf. PG. lxxxiii, 1311S and 1315S).
12. Leo then urged Theodosius and Pulcheria in many letters to wipe out this stain. He proposed that they should remedy this sad state of affairs by summoning a council in Italy to reverse the decrees made at Ephesus. When the Emperor Valentine III, his mother Galla and his wife Eudoxia were entering St. Peter's Basilica, he received them accompanied by an assembly of bishops, and besought them with sighs and tears to do all they could to remedy the evil condition of the Church. The emperor wrote to his brother emperor [in the East], and the royal ladies joined their entreaties to his. But it was all to no purpose. Theodosius was in the hands of evil counselors and did nothing to amend the evil. However, he died suddenly; his sister Pulcheria succeeded him and took as her consort on the throne and in marriage one Marcian. Both of these persons were distinguished by their renown for wisdom and true religion. Then Anatolius, who had been illegally raised by Dioscorus to the see of Constantinople, accepted the letter which St. Leo wrote to Flavian on the Incarnation of our Lord. The remains of Flavian were brought back to Constantinople with great solemnity. The exiled bishops were restored to their sees, and the general hostility to the heresy of Eutyches grew so strong that there scarcely seemed to be any further need for a council. To this result the invasions of the barbarians, which were jeopardizing the safety of the Roman empire, also contributed.
13. Nevertheless, at the emperor's wish and with the pope's approval, a council was held. Chalcedon was a city of Bithynia near the Thracian Bosphorus, within sight of Constantinople, which was situated on the opposite bank. Here, in the vast suburban basilica of St. Euphemia, virgin and martyr, on the 8th of October, assembled the fathers, who had previously met for this purpose in the city of Nicea. They were about 600 in number, all of the East, except for two exiles from Africa.
14. The book of the gospels was placed in the middle; nineteen representatives of the emperor and the senate took their places before the altar rails. The role of apostolic delegates had been entrusted to the devout Bishops Paschasinus of Lilybaeum in Sicily and Lucentius of Ascoli, and to the priests Boniface and Basil. To these was added Julian bishop of Cos, to aid them by his diligent labors. The delegates of the Roman pontiff took the first places among the bishops; they were named first, they spoke first, they signed the Acts first, and by virtue of their delegated authority, they confirmed or rejected the decisions of the others. For example, in the case of the condemnation of Dioscorus, the delegates ratified it in these words: 'The holy and blessed archbishop of great and ancient Rome, Leo, through us and through this holy synod, together with the blessed and praiseworthy Apostle Peter who is the rock and foundation of the Orthodox Faith, has deprived him (Dioscorus) of all episcopal dignity and removed him from every priestly office' (Mansi, Conc. Ampl. Coll. VI, 1047. [Act III]; Schwartz II, Vol. I, pars. altera p. 29  [Act II]).
15. Furthermore, the papal delegates not only exercised the authority of presidents, but their right to this honor of presiding was recognized by all the fathers of the council, as was shown clearly by the letter sent by the synod to St. Leo 'For you', they wrote, 'showed us benevolence in presiding over us in the persons of those who held your place, as the head over the members' (synod of Chalcedon to St. Leo. Ep. xcviii, PL. liv, 951. Mansi vi, 147).
16. It is not necessary for us to relate the whole history of the synod, but we will touch only on the principal points which served to place the truth in full light and to foster the cause of religion. Therefore, since it concerns the dignity of the Apostolic See, we must mention canon XXVIII of this council, by which the next place of honor after the Roman see was granted to Constantinople, as the imperial city. Although there was nothing in this against the divine primacy of jurisdiction of the see of Peter, which indeed was taken for granted, nevertheless, this canon was passed in the absence of the papal legates, and they subsequently objected to it. It was therefore clandestine, surreptitious and lacking in all force of law and, as such, condemned by St. Leo in many letters. Marcian and Pulcheria accepted this rescissory sentence, and even Anatolius wrote to St. Leo excusing his blameworthy boldness: 'With regard to the decree laid down by the recent synod of Chalcedon on behalf of the see of Constantinople, let your Beatitude rest assured that this was not my fault. But it was the desire of the reverend clergy of Constantinople . . . the validity and confirmation of this action being reserved to the authority of your Beatitude' (Anatolius to St. Leo the Great. Ep. cxxxii, 4. PL. liv, 1084. Mansi vi, 278S).
17. Let us come now to the central point of the whole question, i.e. to the solemn definition of the Catholic faith, by which the pernicious error of Eutyches was rejected and condemned. In the fourth session of the sacred synod the representatives of the emperor asked that a new formula of the faith should be composed. But the papal legate, Paschasinus, expressed the feeling of all when he replied that it was not necessary; the ground, he said was sufficiently covered by the creeds already in use, and the canonical documents approved by the Church; among these the letter of St. Leo to Flavin was the most important. 'Thirdly (i.e., after the creeds of Nicea and Constantinople and their explanations by St. Cyril at the council of Ephesus) the writings composed by the holy and apostolic Leo, pope of the universal Church, against the heresies of Nestorius and Eutyches, have already shown what the true faith is. This holy synod likewise holds and follows this same faith' (Mansi, vii, 10 [Act. IV]).
18. It is useful to note here that this very important letter of St. Leo to Flavian concerning the Incarnation of the Word was read in the third session of the council, and hardly had the voice of the reader ceased, when there went up a unanimous cry: 'This is the faith of the Fathers, this is the faith of the Apostles. So we all believe, and so believe all orthodox Christians. Let him be anathema who does not believe this. Peter has spoken through Leo' (Schwartz, II, Vol. I, pars altera, p. 81  [Act. III]; Mansi vi, 871. [Act. II])
19. After this all unanimously agreed that the document of the bishop of Rome fully and perfectly concorded with the creeds of Nicea and Constantinople. Nevertheless, in the fifth session at the requests of the representatives of the Emperor Marcian and the senate, a new definition of the faith was worked out by a select committee of the bishops congregated from diverse lands in the basilica of St. Euphemia. k was made up of a prologue, of the creeds of Nicea and Constantinople (which was promulgated for the first time) and of a condemnation of the doctrine of Eutyches. This rule of faith was approved by the unanimous consent of the council.
20. We think it of importance, Venerable Brethren, to delay a little in elucidating this document of the Roman pontiff, which was such an outstanding vindication of the Catholic faith. Firstly, against the assertion of Eutyches: 'I confess that our Lord was of two natures before their union; after their union I confess that he had only one nature' (St. Leo, Ep. xxviii, 6. PL. liv, 777), the holy bishop, not without a certain indignation, opposed the following clear statement of the luminous truth: 'I am surprised that this absurd and perverse statement should have escaped the severe reprimand of those who gave judgment . . . the Only Begotten Son of God is impiously described as being of two natures before the Incarnation and, equally wickedly to the Word made Flesh is attributed only one nature' (Ibid.). He attacked with equal force and directness the opposite errors of Nestorius. 'It is because there was only one person in both natures, that the Son of God took flesh from the Virgin from whom he was born. And again the Son of God is said to have been crucified and been buried, because he suffered these things in the weakness of his human nature, not in the divinity itself, for through the divinity the only Begotten is co-eternal and consubstantial with the Father. Wherefore in the Creed we all confess "the only Begotten Son of God to have been crucified and buried" ' (Ep. xxviii, 5. PL. liv, 771; cf. Augustinus, Contra Serm. Arianorum, c, 8. PL. xlii, 688).
21. In addition to the distinction of natures in Christ, there is clearly shown here the distinction of the properties and activities, which arise from his double nature, 'Since the properties of each nature remain intact, and they are joined together in one person, majesty accepts lowliness, strength accepts weakness and the Eternal becomes mortal' (Ep. xxviii, 3. PL. liv, 763. cf. St. Leo, Serm. xxi, 2. PL. liv, 192). And again: 'Each nature possesses its properties without defect' (Ep. xxvii, 3. PL. liv, 768. cf. Serm. xxiii, 2. PL. liv, 201).
22. But both sets of properties and activities are attributed to the One Person of the Word, because 'One and the same [Person] is . . . truly the Son of God and truly the Son of Man' (Ep. xxviii, 4. PL. liv, 767). Whence 'In his actions either nature with the co-operation of the other performs what is proper to it; thus the Word performs the part of the Word, and the humanity the part of the humanity' (Ibid). In these expressions appears the use of what is called the Common Application of Terms (Communicatio Idiomatum), which Cyril vindicated against Nestorius. It depends on the firm foundation that both natures subsist by the One Person of the Word begotten before all ages of the Father and born of Mary according to the flesh in the course of time.
23. This sublime doctrine, which is drawn from the gospels and differs in no way from that of the council of Ephesus refutes Eutyches as well as Nestorius. The dogmatic definition of the council of Chalcedon concords with it absolutely and perfectly, for this definition likewise defines two distinct natures and one person in Christ in the following clear and precise words: 'This great and holy oecumenical council condemns those who pretend that there were two natures in the Lord before the union, and imagine that there was only one after the union. Following, therefore, in the traditions of the holy Fathers we teach that all with one voice confess that the Son [of God] and our Lord Jesus Christ are one and the same, and that he is perfect in his divinity, perfect in his humanity, true God and true man, made of a rational soul and a body, consubstantial with the Father in his divinity, and the same also in his humanity received from the Virgin Mary in recent times for our sake and for our salvation, one and the same Christ, the Son, the Lord, the Only Begotten, having two natures without confusion, change, division or separation; the distinction between the natures was not removed by the union, but the properties of each remain inviolate and are joined together in one person. He is not sundered or divided into two persons, but is one and the same Son and only Begotten God the Word, the Lord, Jesus Christ' (Mansi. vii, 114 and 115).
24. If anyone asks how it is that the statements of the council of Chalcedon are of such outstanding excellence in their clarity and their efficiency in the refutation of error, we reply that this arises from the fact that ambiguities had been removed and a most exact terminology was used. For in the Chalcedonian definition of the faith and the same concept underlies the terms 'Person' (Prósopon) and 'Hypostasis' (Upóstasis); the term 'Nature' has a totally different sense, and its meaning is never given to the other words. So that the Nestorians and Eutychians of old and certain modern writers err when they maintain that the council of Chalcedon corrected the decision of the council of Ephesus. Rather the one perfected the other, so that a synthesis or composition of the main Christological doctrine was available in fuller form for the second and third oecumenical councils of Constantinople.
25. It is indeed sad that the ancient adversaries of the council of Chalcedon (also called Monophysites) should have rejected this doctrine, so lucid, so coherent and so complete, on the strength of certain badly understood expressions of ancient writers. While they rejected the absurd teaching of Eutyches about the mixture of natures in Christ, they obstinately clung to the well-known expression: 'One Incarnate nature of the Word God'. This expression had been used by Cyril of Alexandria (who took it from St. Athanasius) with a perfectly correct meaning, since he used the term 'nature' to signify 'person'. The Fathers of Chalcedon, therefore, totally removed what was ambiguous or liable to cause error in these expressions. For they applied the same terms as are used in the theology of the Trinity, to the exposition of our Lord's Incarnation. Thus they made 'nature' and 'essence' (essentia) the same, and likewise 'Person' and 'Hypostasis', and they treated the latter two names as totally different in meaning, from the former two. Their approach, on the other hand, had made 'nature' the equivalent of' Person' not of 'essence' (essentia).
26. For the reason just given there are today some separated bodies in Egypt, Ethiopia, Syria, Armenia and elsewhere, who go wrong mainly in their use of words in defining the doctrine of the Incarnation. This may be demonstrated from their liturgical and theological books.
27. Moreover, in the twelfth century, a writer of the highest repute, among the Armenians, clearly expounded his views of this matter in these words: 'We speak of Christ as one nature, not to imply confusion as does Eutyches, nor diminution, as does Apollinaris, but in the sense of Cyril of Alexandria, who in his book Scholiorum Adversus Nestorium says, "There is one nature of the Incarnate Word as the Fathers taught". And we also teach this according to the tradition of the saints, but not according to the opinion of heretics. For they introduce confusion and change and alterations into the union in Christ. We say there is one nature referring to the hypostasis, which you also speak of in Christ; and this is correct and granted by us, and equally valid is our own expression: "One Nature." Nor do we refuse to say "two Natures", provided there is no implication of the division maintained by Nestorius, but the expression is used against the confusion introduced by Eutyches and Apollinaris' (Nerses iv, 1173) in his Libellum Confessionis Fidei to the Emperor Manuel Comnenus (cf. I. Capelletti S. Narsetis Claiensis Armenorum Catholici, Opera. I, Venice 1836, pp. 182-83).
28. If then it is the climax of gladness and the consummation of holy joy, when that comes to pass which the Psalmist said: 'Behold how good and how pleasant it is for brethren to live together in unity' (Ps. 132, I); if then the glory of God combined with the greatest profit for all is apparent when the sheep of Christ are joined together in the fullness of truth and the fullness of charity, let those whom with sorrow and love we have mentioned above, consider whether it is right and expedient that, principally on account of the original ambiguity of certain words, they should still hold apart from the one Holy Church, founded on sapphires (cf. Is. liv, 11), that is to say, on the Prophets and Apostles, on the supreme corner stone itself, Christ Jesus (cf. Eph. ii, 20).
29. There is another enemy of the faith of Chalcedon, widely diffused outside the fold of the Catholic religion. This is an opinion for which a rashly and falsely understood sentence of St. Paul's Epistle to the Philippians (ii, 7), supplies a basis and a shape. This is called the kenotic doctrine, and according to it, they imagine that the divinity was taken away from the Word in Christ. It is a wicked invention, equally to be condemned with the Docetism opposed to it. It reduces the whole mystery of the Incarnation and Redemption to empty the bloodless imaginations. 'With the entire and perfect nature of man' - thus grandly St. Leo the Great - 'He Who was true God was born, complete in his own nature, complete in ours' (Ep. xxviii, 3. PL. liv, 763. Cf. Serm. xxiii, 2. PL. lvi, 201).
30. While there is no reason why the humanity of Christ should not be studied more deeply also from a psychological point of view, there are, nevertheless, some who, in their arduous pursuit, desert the ancient teachings more than is right, and make an erroneous use of the authority of the definition of Chalcedon to support their new ideas.
31. These emphasize the state and condition of Christ's human nature to such an extent as to make it seem  something existing in its own right (subjectum quoddam sui juris), and not as subsisting in the Word itself. But the council of Chalcedon in full accord with that of Ephesus, clearly asserts that both natures are united in 'One Person and subsistence', and rules out the placing of two individuals in Christ, as if some one man, completely autonomous in himself, had been taken up and placed by the side of the Word. St. Leo not only adheres to this opinion (i.e. that of Chalcedon), but he also indicates the source whence he derives his sound doctrine. 'Whatever', he says, 'we have written has manifestly clearly been taken from the doctrine of the Apostles and of the Gospels' (Ep. clii. PL. liv, 1123).
32. It is indeed the truth that from the earliest times and in the most ancient writings, sermons and liturgical prayers, the Church openly and without qualification professes that our Lord Jesus Christ, the only Begotten Son of the Eternal Father, was born on earth, suffered, was nailed to the cross, rose from the sepulcher and ascended into heaven. And, further, the words of sacred Scripture give to the one Christ, the Son of God, human attributes, and to the same [Christ] the Son of Man, divine attributes.
33. Thus St. John the Evangelist declares: 'The Word was made flesh' (John i, 14). St. Paul writes of him: 'When he was in the form of God . . . he humbled himself and became obedient even unto death' (Phil. ii, 6-8); or again: 'But when the fullness of time was come, God sent his Son, made from a woman' (Gal. iv, 4), and our Divine Redeemer himself put the matter beyond doubt when he says: 'I and the Father are One' (John x, 30); and again, 'I went out from the Father and I came into the world' John xvi, 28). The divine origin of our Redeemer is also manifest from this passage of the Gospel: 'I came down from heaven, not that I should do my own will, but the will of him that sent me' (John vi, 38). And again: 'He who descended, this is he who ascended above all the heavens' (Eph. iv, 10). St. Thomas Aquinas explains this last sentence thus: 'He who descended, this is the same as he who ascended. By these words is signified the unity of the person of God and man. For the Son of God came down by taking human nature, but the Son of Man ascended according to his human nature to the sublimity of eternal life. And so he is the same Son of God who came down and Son of Man who went up' (St. Thomas, Comm. in Ep. ad Eph. c iv. lect. iii circa finem).
34. This same doctrine was set forth by our predecessor Leo the Great in these words: 'What principally contributed to the justification of mankind was that the only Begotten Son of God deigned to become the Son of Man, so that being God smoúsios to the Father, that is of the same substance, the same [person] should exist as true man consubstantial with his mother in the flesh; we rejoice over both these things, since only by both are we saved; we admit no division of the visible from the invisible, the corporeal from the incorporeal, the passible from the impassible, the palpable from the impalpable, the form of the servant from the form of God. For although he remains the one from eternity, he began to be the other in time; these two have met in unity and can have neither separation nor end' (St. Leo. Serm. 30, 6. PL. liv, 233S).
35. Only, therefore, if we adhere to the holy inviolate faith, that there is one Person in Christ, that of the Word, in which two natures entirely distinct from each other, the divine and the human, distinct also in their properties and activities, converge - only if we adhere to this doctrine does the magnificence and the fatherly mercy of our ineffable redemption shine forth.
36. O height of the mercy and justice of God, who came to the rescue of guilty creatures and made them sons unto Himself! How the heavens bent down towards us, the wintry frosts vanished, the flowers appeared in our land, and we became new men, a new creation, a new structure, a holy people, a heavenly offspring. Truly the Word suffered in his flesh and shed his blood on the cross and paid for us sinners to the Eternal Father the superabounding price of our satisfaction. Hence it is that the certain hope of salvation sheds its light on those who in genuine faith and ardent charity adhere to him, and with the help of the graces that flow from him, produce the fruits of justice.
37. The very recalling of the memory of these distinguished and glorious events in the history of the Church naturally leads us to turn our thoughts to the Orientals with a yet more loving warmth of paternal affection. For the oecumenical council of Chalcedon is a monument of their outstanding glory, and one which, without doubt, will live throughout the ages. For in this council under the leadership of the Apostolic See, an assembly of 600 Oriental bishops vigilantly defended and wonderfully expounded against the rashness of the innovator, the doctrine of the unity of Christ, in whose person meet without confusion two distinct natures, the divine and the human. But alas! for long centuries many of those who dwell in the East have unhappily fallen away from the unity of the Mystical Body of Christ, of which the hypostatic union is the most luminous prototype. Would it not be holy, salutary and in accordance with the will of God that at last all these should return to the one sheepfold of Christ?
38. For our part we desire that they should always bear in mind that Our thoughts are thoughts of peace and not of affliction (cf. Jer. xxix, 11). It is well known, moreover, that we have demonstrated this by our actions. If, under the pressure we boast of this, then we boast in the Lord, who is the giver of every goodwill. For we have followed in the path of our predecessors and worked diligently to facilitate the return of the Oriental peoples to the Catholic Church. We have guarded their legitimate rites. We have promoted the study of their affairs. We have promulgated beneficent laws for them. We have shown deep solicitude in our dealings with the sacred council of the Roman curia for oriental affairs. We have bestowed the Roman purple on the patriarch of the Armenians.
39. When the recent war was waging and producing its fruits of famine, want and disease, we made no distinction between them and those who are accustomed to call us Father, but sought everywhere to relieve the increasing misery; we strove to help widows, children, old people and the sick. We would have been happier truly had our means been equal to our desires! Let those then who, through the calamities of time, have been cut off, not be slow to pay due respect to this divinely erected and unbroken rock, this Apostolic See for whom to rule is to serve. Let them bear in mind and imitate Flavian, that second John Chrysostom, in his sufferings for justice; and the fathers of Chalcedon, those most worthy members of the Mystical Body of Christ; and Marcian, that strong, gentle and wise ruler; and Pulcheria, that resplendent lily of inviolate royal beauty. From such a return to the unity of the Church we foresee that there would flow a rich fountain of blessings unto the common good of the whole Christian world.
40. Truly we are aware of the accumulation of prejudice that tenaciously prevents the happy fulfillment of the prayer offered by Christ at the last Supper to his Eternal Father for the followers of the Gospel: 'That they may be one' (John xvii, 21). But we know also that such is the strength of prayer, when those who pray are joined together in a common fervor, a strong faith, and a clear conscience, that it can lift up a mountain and cast it headlong into the sea (cf. Mark ii, 23). We desire then and we wish that all those who have at heart an earnest invitation to Christian unity - and surely no one who belongs to Christ would belittle the importance of this matter - should pour forth their united prayers and supplications to God, from whom comes all unity, order and beauty, that the praiseworthy desires of every right-thinking person may soon be brought to fulfillment. Let research be made without jealousy or anger to straighten out the path by which this good may be reached; let us bear in mind that today we are accustomed to retrace and weigh the events of bygone ages more calmly than in the past.
41. Furthermore, there is another reason which demands the immediate coalition of all ranks under the single sign of the cross in order to oppose the turbulent attacks of the infernal enemy. Who is not horror struck at the ferocity and hatred with which the enemies of God, in many parts of the world, threaten to eradicate and wipe out everything divine and Christian? All those who are signed with the sacred character of baptism and are deputed by their state to fight the good fight of Christ, cannot remain disunited and dispersed against the confederated ranks of their enemies.
42. The chains, the agonies, the tortures, the groans, the blood of the innumerable multitude of persons, known and unknown, who recently and even today, have suffered and still suffer on account of their courage and constancy in the profession of their faith, cry out to all with louder and louder voice as the days go by, to embrace the unity of the Church.
43. Our hope for the return of these brothers and sons separated from the Apostolic See is made stronger by this harsh crucifixion and these bloody martyrdoms of so many other brothers and sons. Let no one neglect or impede the saving work of God. To the blessings and joys of this return we exhort and urge all those who follow the erroneous doctrines of the Nestorians and the Monophysites. Let them be sure that we should think it the brightest gem in the crown of our apostolate if the opportunity were given us of treating with honor and charity those who are the more dear to us because the long period of their withdrawal has excited in us the greater desire [for their return].
44. This is our final wish, venerable brethren, that when through your diligence the memory of the sacred council of Chalcedon is celebrated, all should be urged to adhere with a most firm faith to Christ our Redeemer and our King. Let no one be deceived by the fallacies of human philosophy or led astray by the quibbles of human speech; let no one corrupt by perverse innovation or weaken by doubt the dogma confirmed at Chalcedon, namely, that there are in Christ two true and perfect natures, the divine and the human, not confused one with another, but joined together and subsisting in the one person of the Word. Let all then be joined in a close bond with the author of our salvation, who is 'the way of holy life, the truth of divine doctrine, and the life of eternal happiness' (St. Leo Serm. lxxii, I. PL. liv, 390). Let all love our restored nature in him, let them cultivate the liberty bought by him; let them cast out the folly of the aged world; let them turn with joy to the wisdom that is ignorant of old age, the wisdom of spiritual infancy.
45. May God Who is One in Three, whose nature is goodness, whose will is power, receive these burning desires, through the intercession of the Blessed Virgin Mary, Mother of God, the Holy Apostles Peter and Paul, and Euphemia the Virgin Martyr, who triumphed at Chalcedon. Do you, venerable brethren, add your prayers to ours for this cause, and see that what we have written to you is made known as widely as possible. Giving you now our thanks for this, to you and to all priests and to all Christ's faithful, whose spiritual advancement lies in your care, lovingly we bestow the apostolic blessing. May it enable you to take with greater readiness Christ's yoke upon you, a yoke that is neither heavy nor harsh, and may you become more and more like to him in humility, of whose glory you hope to be sharers.
Given at St. Peter's Basilica, Rome, on the 8th September, the feast of the birthday of the Virgin Mary, in the year 1951, the thirteenth of our pontificate.
1. Translation made for the E.C.Q. from the Latin text published in L'Osservatore Romano (13 settembre 1951).
2. The text published in L'Osservatore Romano includes the phrase "at least psychologically." This phrase (saltem psychologicae) was omitted in the text published in the Acta Apostolicae Sedis, 43 (1951), p. 638, lines 15-17: "Hi humanae Christi naturae statum et conditionem ita provehunt ut eadem reputari videatur subiectum quoddam sui iuris, quasi in ipsius Verbi persona non subsistat."