Encyclical of Pope Pius XII on Saint Cyril of Alexandria
1. St. Cyril, Patriarch of Alexandria, glory of the Eastern Church and celebrated champion of the Virgin Mother of God, has always been held by the Church in the highest esteem, and We welcome the opportunity of recalling his merits in this brief Letter, now that fifteen centuries have passed since he happily exchanged this earthly exile for his heavenly home.
2. Our Predecessor St. Celestine I hailed him as 'good defender of the Catholic faith,' as 'excellent priest,' as 'apostolic man.' The ecumenical Council of Chalcedon not only used his doctrine for the detecting and refuting of the latest errors, but went so far as to compare it with the learning of St. Leo the Great; and in fact the latter praised and commended the writings of this great Doctor because of their perfect agreement with the faith of the holy Fathers. The fifth ecumenical Council, held at Constantinople, treated St. Cyril's authority with similar reverence and many years later, during the controversy about the two wills in Christ, his teaching was rightly and triumphantly vindicated, both in the first Lateran Council  and in the sixth ecumenical Council, against the false charge of being tainted with the error of Monothelitism. He was, as Our saintly Predecessor Agatho proclaimed, 'a defender of the truth' and 'a consistent teacher of the orthodox faith.'
3. We therefore think it proper in this Letter to give some account of his spotless life, faith, and virtue; and this for the benefit of all, but especially of those who belong to the Eastern Church and therefore have good reason to be proud of this luminary of Christian wisdom, this valiant hero of the apostolate.
4. Born of distinguished family, he was raised to the See of Alexandria - so tradition tells us - in the year 412. His first conflict was with the Novatians and others who attacked the integrity and purity of the faith, and against these he preached, wrote, and issued decrees, ever alert, ever fearless. Later, when the blasphemous heresy of Nestorius began to spread gradually through the East the watchful Pastor was quick to perceive the growth of these new errors and zealous in protecting his flock against them. Throughout this stormy period, and especially at the Council of Ephesus, he showed himself the invincible champion and learned teacher of the divine maternity of the Virgin Mary, of the hypostatic union in Christ, and of the Primacy of the Roman Pontiff. But the leading part which St. Cyril played in these important events has already been admirably described and explained by Our immediate Predecessor of happy memory Pius XI, in the Encyclical Lux Veritatis  with which in the year 1931 he celebrated the fifteenth centenary of that ecumenical Council, and therefore it would be superfluous to enter into the details of it here.
5. For Cyril, however, it was not enough to fight vigorously against heresies as they arose, not enough to guard the integrity of Catholic doctrine with energy and solicitude and throw the fullest possible light upon it; he was also untiring in his labors to recall his erring brethren to the straight path of the truth. For when the Bishops of the Province of Antioch were still refusing to recognize the authority of the holy Council of Ephesus, it was due to his efforts that they were at length, after long vicissitudes, brought to complete agreement. And it was only after he had succeeded with God's help in accomplishing this happy reunion and in guarding and securing it against misconceptions that, being now ripe for the reward of everlasting glory, he was taken up to heaven in the year 444, mourned by all men of good will.
6. The faithful of the Eastern rite not only count St. Cyril among the 'ecumenical Fathers,' but also honor him with the deepest veneration in their liturgical prayers. Thus the Greeks chant in the Menaia of the 9th June:
Enlightened in mind by the flames of the Holy Spirit, thou hast uttered oracles even as the sun sends forth its rays. To the ends of the earth and to all the faithful thy teaching has gone forth, O most blessed Saint, illuminating all sorts and conditions of men, and dispelling darkness of heresy by the power and strength of that Light who was born of the Virgin.
7. And the sons of the Eastern Church have every right to rejoice and take pride in this holy Father as one who is peculiarly and especially their own. For he is above all pre-eminent in those three qualities which have so greatly distinguished the other Fathers of the East: an outstanding sanctity of life, marked by a specially ardent devotion to the august Mother of God; exceptional learning, such that the Sacred Congregation of Rites, by a decree of the 28th July, 1882, declared him a Doctor of the Universal Church; and finally an energetic zeal in fearlessly repelling the attacks of heretics, in asserting the Catholic faith, and in defending and spreading the Gospel to the full extent of his power.
8. But our great joy in the deep veneration which all the Christian peoples of the East have for St. Cyril is mingled with an equal regret that not all of them have come together into that desired unity of which he was the ardent lover and promoter. And especially do We deplore that this should be so at the present time, when it is above all necessary that all Christ's faithful ones should labor together in heart and endeavor for union in the one Church of Jesus Christ, so that they may present a common, serried, united, and unyielding front to the daily growing attacks of the enemies of religion.
9. For this to be brought about it is absolutely necessary that all should take St. Cyril as their model in striving for a true harmony of souls, a harmony established by that triple bond which Christ Jesus, the Founder of the Church, willed to be the supernatural and unbreakable link provided by Him for binding and holding together: the bond of one faith, of one charity towards God and all men, and of one obedience and rightful submission to the hierarchy established by the Divine Redeemer Himself. As you know full well, Venerable Brethren, these three bonds are so necessary that, if any one of them be lacking, true unity and harmony in the Church of Christ is unthinkable.
10. Throughout the troubled times of his life on earth the Patriarch of Alexandria taught all men, both by word and by conspicuous example, how this true harmony is to be achieved and steadfastly maintained - and We would have him do this also today.
11. And first, as regards the unity of the Christian faith, St. Cyril's untiring energy and unyielding tenacity in guarding it are well known.
We (he writes) , to whom the truth and the doctrines of truth are most dear, refuse to follow these (heretics); we, taking the faith of the holy Fathers as our guide, will guard against all errors the divine revelation committed to our trust.
12. In this cause he was prepared to fight even to death and at the cost of the greatest sufferings:
For the faith that is in Christ (he says) it is my greatest wish to toil, to live, and to die. Only let the faith be kept safe and untarnished . . . and no insults, no injuries, no reproaches can move me.
13. And he expressed his valiant and noble desire for the palm of martyrdom in these generous words:
I have made up my mind that for the faith of Christ I will undergo any labor, suffer any torments, even those tortures which are counted most grievous, until I am granted the joy of dying for this cause. . . . For if we are deterred by the fear of suffering some misfortune from preaching God's truth for His glory, with what countenance can we preach to the people in praise of the sufferings and triumphs of the holy martyrs?
14. Animated discussions about the new Nestorian heresy were going on in the monasteries of Egypt, and the watchful Bishop writes to warn the monks of the fallacies and dangers of this doctrine, not, however, in order to foment dissensions and controversies, but (he says, so that if any should chance to attack you, you may be able to oppose their vanities with the truth, and so not only yourselves be saved from the disaster of error but also be able fraternally to convince others with suitable arguments, and thus help them to preserve forever in their hearts the pearl of that faith was delivered through the holy Apostles to the Churches.
15. Moreover, he plainly saw - as may be gathered easily from a reading of his letters on the subject of the Antiochene Bishops - that this Christian faith, which we must at all costs preserve and protect, has been delivered to us through the Sacred Scriptures and through the teaching of the Holy Fathers, and is clearly and authentically set forth by the living and infallible teaching authority of the Church. Thus, when the Bishops of the Province of Antioch claimed that for the restoration and maintenance of peace it was enough if they kept the faith of the Council of Nicaea, St. Cyril, while himself firmly adhering to the Nicene Creed, also required of his brethren in the Episcopate, as a condition of reunion, that they should reject and condemn the Nestorian heresy. For he quite well understood that it is not enough to accept willingly the ancient pronouncements of the teaching office of the Church, but that it is also necessary to believe humbly and loyally all that is subsequently enjoined upon our faith by the Church in virtue of her supreme authority.
16. Even on the plea of promoting unity it is not allowed to dissemble one single dogma; for, as the Patriarch of Alexandria warns us, 'although the desire of peace is a noble and excellent thing, yet we must not for its sake neglect the virtue of loyalty in Christ.' Consequently, the much desired return of erring sons to true and genuine unity in Christ will not be furthered by exclusive concentration on those doctrines which all, or most, communities glorying in the Christian name accept in common. The only successful method will be that which bases harmony and agreement among Christ's faithful ones upon all the truths, and the whole of the truths, which God has revealed.
17. Let Cyril of Alexandria be a model to all in the energy and fortitude with which he defended the faith and kept it inviolate. No sooner did he discover the error of Nestorius than he wrote letters and other works in refutation of it, appealed to the Roman Pontiff and, acting in his name at the Council of Ephesus, crushed and condemned the growing heresy with admirable learning and unflinching courage. The result was that, when Cyril's 'dogmatic' letter had been publicly read, all the Fathers of the Council acclaimed it by solemn verdict as being in complete accordance with the true faith.
18. His apostolic energy led to his being unjustly deposed from his episcopal see, insulted by his brethren, condemned by an illegitimate council, and subjected to prison and many hardships; but he bore all with unruffled and invincible courage. And not only did he oppose the Bishops who had gone astray from the path of truth and unity; he did not hesitate, in the conscientious discharge of his holy duty, openly to resist even the Emperor himself. In addition to all this, as everybody knows, he wrote countless works in support and defense of the Christian faith, works which bear striking testimony to his extraordinary learning, his intrepid courage, and his pastoral zeal.
19. But faith must be accompanied by charity, charity which unites us all with one another and with Christ; charity which, under the inspiration and motion of the Divine Spirit, welds the members of the Mystical Body of the Redeemer together by an unbreakable bond.
20. This charity, however, must not refuse to embrace also those who have gone astray from the path of truth; and of this we may see an example in St. Cyril's remarkable conduct. Vigorously though he fought against the heresy of Nestorius, yet such was the ardent charity which animated him that, as he openly declared, he yielded to none in his love for Nestorius himself. And in this he was right. Those who wander from the straight path are to be considered as ailing brethren, and treated with gentle and loving care. The Patriarch of Alexandria's prudent advice on this point is worth quoting:
This is a matter calling for the greatest moderation. . . . In many cases a violent clash only drives people to insolence; and it is better to treat your opponents with kindness than to make them suffer by applying the rigor of the law. If they were physically ill you would handle their bodies gently; so in like manner prudence is the best medicine to use in the treatment of ailing souls. Gradually they too will be brought to a proper state of mind.
21. And elsewhere he adds:
We followed the example of skillful doctors, who do not immediately apply the drastic remedies of fire and steel as soon as disease or hurt have appeared in the human body; first they soothe the wound with milder liniments, only when the proper time has come do they use cautery and the knife. 
22. Filled with this spirit of compassion and loving-kindness towards erring souls, he professes that he is 'the friend of peace and altogether averse to controversy and quarrels; a man, in short, who desires to love everybody and to be loved by everybody in return.'
23. The Holy Doctor's ready inclination for peace was shown especially when he mitigated his earlier severity and devoted his energies to bringing about reunion with the Bishops of the Province of Antioch. Referring to their ambassador he writes:
He was probably expecting great difficulty in persuading us that it was needful to unite the Churches in peace and harmony, to deprive the heterodox of the excuse for mockery, and to repel the forces of diabolical malice. He found us, on the contrary, so much disposed to this course that he met with no difficulty whatever. For we are mindful of our Savior's words: 'My peace I give to you, my peace I leave unto you.'
24. Among the obstacles to this reunion were the twelve 'Chapters' which St. Cyril had drawn up at the Synod of Alexandria, and which were rejected by the Antiochene Bishops as unorthodox because they spoke of a 'physical union' in Christ. With the utmost readiness the Patriarch, while not withdrawing or repudiating these writings - for the doctrine they contained was orthodox - nevertheless wrote several letters to explain his meaning and remove any possibility of misunderstanding, and so clear the way to peace and harmony. These explanations he gave to the Bishops, treating them 'as brethren, and not as adversaries.' 'For the sake of the peace of the Churches,' he says elsewhere, 'and to prevent them from being divided by difference of opinion, it is worthwhile to waive one's dignity.' In this way St. Cyril's charity bore in abundance the desired fruits of peace; and when at last it was granted him to see the dawn of that reconciliation, when the Bishops of the Province of Antioch had condemned the Nestorian heresy and he was able to embrace them as brothers, he exclaimed with holy joy:
'Let the heavens rejoice and let the earth be glad.' For the middle wall of partition has been broken down; that which had caused us grief is now at peace; every matter of contention has now been removed; Christ, the Savior of us all, has granted peace to His Churches.
25. As it was in those times long past, Venerable Brethren, so will it be also today. More effective than anything else for promoting that reunion of all our separated sons with the one Church of Christ for which all good men are striving, will be a sincere and practical goodwill, with the help and inspiration of God. The fruit of such goodwill is mutual understanding, an understanding which Our Predecessors have sought so earnestly to foster and increase by various means, in particular by founding in Rome the Pontifical Institute of Higher Oriental Studies.
26. This goodwill implies also a proper respect for those traditions which are the special heritage of the peoples of the East, whether these be concerned with the sacred liturgy and the hierarchical Orders or with other observances of the Christian life, so long as they are in keeping with the true faith and with the moral law. Each and every nation of Oriental rite must have its rightful freedom in all that is bound up with its own history and its own genius and character, saving always the truth and integrity of the doctrine of Jesus Christ.
27. We would have this to be known and appreciated by all, both by those who were born within the bosom of the Catholic Church, and by those who are wafted towards her, as it were, on the wings of yearning and desire. The latter especially should have full assurance that they will never be forced to abandon their legitimate rites or to exchange their own venerable and traditional customs for Latin rites and customs. All these are to be held in equal esteem and equal honor, for they adorn the common Mother Church with a royal garment of many colors. Indeed this variety of rites and customs, preserving inviolate what is most ancient and most valuable in each, presents no obstacle to a true and genuine unity. It is especially in these times of ours, when the strife and discord of war have estranged men's hearts from one another nearly all the world over, that all must be impelled by the stimulus of Christian charity to promote union in Christ and through Christ by every means in their power.
28. But the work of faith and charity would remain incomplete and powerless to establish unity firmly in Christ Jesus, unless it rested upon that unshaken rock upon which the Church is divinely founded, that is, upon the supreme authority of Peter and his Successors.
29. And this fact is proved clearly by the Patriarch of Alexandria's conduct in this important matter. Both in his work of repressing the Nestorian heresy and in that of reconciling the Bishops of the Province of Antioch, he remained constantly in close union with this Apostolic See.
30. As soon as the watchful Prelate perceived that the errors of Nestorius were spreading and growing, with increasing danger to the orthodox faith, he wrote to Our Predecessor St. Celestine I in the following terms:
Since God requires us to be vigilant in these matters, and since the ancient custom of the Church persuades us that questions of this kind should be communicated to Your Holiness, I write, driven by necessity.
31. In reply the Roman Pontiff writes that 'he had embraced Cyril as though present in his letter,' since it was clear that 'they were of one mind concerning the Lord.' So orthodox was the faith of this Doctor that the Sovereign Pontiff delegated to him the authority of the Apostolic See, in virtue of which he was to give effect to the decrees which had already been issued against Nestorius in the Synod of Rome. And it is evident, Venerable Brethren, that at the Council of Ephesus the Patriarch of Alexandria acted as the legal representative of the Roman Pontiff; for, although the latter also sent his own Legates, the chief instruction he gave them was that they should support the action and the authority of St. Cyril. It was therefore in the name of the Sovereign Pontiff that he presided at this holy Council, and he w as the first to sign its proceedings. Indeed, so manifest was the agreement between the Apostolic See and that of Alexandria that, after the public reading of St. Celestine's letter in the second session of the Council, the Fathers exclaimed:
This judgment is just. To Celestine, a new Paul; to Cyril, a new Paul; to Celestine, guardian of the faith; to Celestine, who is of one mind with the Synod, the whole of this Synod gives thanks. One Celestine, one Cyril, one faith of the Synod, one faith of the whole world.
32. No wonder, then, that Cyril could write shortly afterwards:
To my orthodox faith the Roman Church has borne witness, and so too has a holy Synod gathered together, so to speak, from the whole of the earth that is under heaven.
33. The same constant union of St. Cyril with the Apostolic See is clearly apparent in all that he did to effect and consolidate reunion with the Bishops of the Province of Antioch. Although Our Predecessor St. Celestine approved and ratified all that the Patriarch of Alexandria had done at the Council of Ephesus, he made an exception for the sentence of excommunication which the President of the Council, together with the other Fathers, had passed upon the Antiochenes. The Sovereign Pontiff wrote:
With regard to those who appear to have been of one mind and one impiety with Nestorius, . . . We have read the sentence you have passed upon them. Nevertheless, We also decree what seems to Us opportune. In these cases many circumstances have to be considered which the Apostolic See has always borne in mind . . . Should the Bishop of Antioch offer hope of being corrected, We would have Your Fraternity come to some Agreement with him by letter. . . . We must trust that by the divine mercy all may return to the way of truth.
And it was in obedience to this instruction of the Roman See that St. Cyril began to take measures for bringing about reunion with the Bishops of the Province of Antioch.
34. Meanwhile, after St. Celestine's holy death, a report having been spread that his Successor St. Xystus III had objected to the deposition of Nestorius from his episcopal see, the Patriarch of Alexandria refuted these rumors: '(Xystus) has written in terms agreeing with the holy Synod,' he said; 'he has ratified all its proceedings and is of one mind with Us.'
35. All this shows plainly enough that St. Cyril was in perfect accord with this Apostolic See and that Our Predecessors regarded his measures as their own, and gave them their complete approval. Thus St. Celestine, after other numerous proofs of his confidence in St. Cyril and his gratitude towards him, writes as follows:
We rejoice in the vigilance shown by Your Holiness, wherein you surpass even the example set by your predecessors, themselves always defenders of the orthodox faith. . . . You have laid bare all the wiles of crafty teachers. . . . This is indeed a great triumph that you have won for our faith, in asserting our truth so valiantly and thus overcoming opposition to it by the testimony of Holy Writ.
36. And when St. Xystus III, his successor in the Papacy, had received news from the Patriarch of Alexandria that peace and reconciliation had been established, he wrote to him joyfully as follows:
Behold while We were suffering great anxiety - for We would have none to perish -Your Holiness' letter brought Us news that the Body of the Church has been made whole again. Now that the structure of its members has been fitted together again, We see none outside or gone astray, for their one faith testifies that all are at their places within. . . . The whole brotherhood has now come to agreement with the blessed Apostle Peter; behold here an auditorium befitting the hearers, befitting the things heard therein. . . . Our brethren are come back to us, to us whose common aim had been to attack the disease that we might bring health to souls. . . . Rejoice, beloved Brother, rejoice in triumph over the return of our brethren to us. The Church had been seeking those whom she has now received back again. If we would not have any even of the little ones to perish, how much more must we rejoice now that their rulers are safe.
37. It was with the consolation which he derived from these words of Our Predecessor that the Prelate of Alexandria, this invincible champion of the orthodox faith, this most earnest promoter of Christian unity, passed to his rest in the peace of Christ.
38. And We, Venerable Brethren, as We celebrate the fifteenth centenary of this heavenly birthday, have no more earnest desire than to see all who can be called Christians take St. Cyril as their model, and work ever more and more zealously for the happy return of our separated brethren in the East to Us and to the one Church of Jesus Christ. Let there be in all one faith inviolate; in all one charity, uniting all together in the mystical Body of Jesus Christ; in all one earnest and practical loyalty to the See of Blessed Peter.
39. The furtherance of this worthy and meritorious work must be the special endeavor of those who live in the East and who, by mutual esteem, by friendly intercourse, and by the example of their spotless life, can more easily induce our separated brethren, and especially their clergy, to become reunited with the Church. But all the faithful, besides, can contribute by their prayers and supplications that God may establish throughout the world the one Kingdom of the divine Redeemer and His one fold for all.
40. Indeed, to all alike We recommend in a particular way that most effective aid, which in any work for the saving of souls must take the first place both in order of time and efficacy: fervent, humble, and confident prayer to God. And We would have them invoke the most powerful patronage of the Virgin Mother of God, that, through the gracious intercession of this most loving Mother of us all, the Divine Spirit may enlighten the minds of Eastern peoples with His heavenly light, and that all of us may be one in the one Church which Jesus Christ founded, and which that same Spirit, the Paraclete, nourishes with an unceasing rain of graces and stirs to sanctity.
41. To seminarists and to pupils of other colleges We specially commend the observance of the 'Day for the East'; on that day let prayers more than usually fervent be made to the Divine Shepherd of the whole Church, and let the hearts of the young be stimulated to a burning zeal for the achievement of this holy unity. Finally, let all, alike those who are in Sacred Orders and those who, as members of Catholic Action and other associations, are co-operating with the hierarchy of the Church, perseveringly direct their prayers, their writings, their discourses, to promoting this desired union of all Easterns with the common Father.
42. And God grant that this Our fatherly and urgent appeal may be given a friendly hearing by those separated Bishops and their flocks who, though divided from Us, yet admire and venerate the Patriarch of Alexandria as a hero of their own land. Let this great Doctor's teaching and example move them to restore peace by means of that triple bond which he himself so strongly urged as indispensable, and by which the divine Founder of the Church willed all His sons to be united together. Let them remember that We, by the Providence of God, to-day occupy that same Apostolic See to which the Patriarch of Alexandria felt bound in conscience to appeal, when he wanted to provide a sure defense of the orthodox faith against the errors of Nestorius, and to set a divine seal, so to speak, upon the reconciliation achieved with his separated brethren. And let them be assured that the same charity which inspired Our Predecessors inspires Us too; and that the chief object of Our constant desires and prayers is that the age-old obstacles between us may be happily removed, and the day dawn at last when there shall be one flock in one fold, all obedient with one mind to Jesus Christ and to His Vicar on earth.
43. We address a particular appeal to those of Our separated sons in the East who, though they hold St. Cyril in great veneration, yet refuse to acknowledge the authority of the Council of Chalcedon, because it solemnly defined that there are two natures in Jesus Christ. Let these bear in mind that the decrees which were later issued by the Council of Chalcedon as new errors arose are in no way contrary to the teaching of the Patriarch of Alexandria. As he himself clearly says,
Not everything that heretics say is to be denied and rejected out of hand, for they profess much of what we also assert. . . . So it is also with Nestorius. He is not wrong in saying that there are two natures in Christ, so far as he means that the flesh is distinct from the Word of God; for the nature of the Word is indeed distinct from the nature of flesh. But he does not profess the union of the natures as we do.
44. Moreover, there is reason to hope that the modern followers of Nestorius also, if they examine St. Cyril's writings with unprejudiced mind and study them carefully, may see the path of truth Iying open before them and, through the inspiration and help of God, feel themselves called back to the bosom of the Catholic Church.
45. It only remains for Us now, Venerable Brethren, on the occasion of this fifteenth centenary of St. Cyril, to implore the most powerful patronage of this Holy Doctor for the whole Church, and especially for all those in the East who glory in the Christian name, imploring for our separated brethren and children that blessing which he himself once so joyfully described:
Behold the sundered members of the Body of the Church are reunited once again, and no further discord remains to divide the ministers of the Gospel of Christ.
46. Sustained by this happy hope, We grant most lovingly in the Lord to each and every one of you, Venerable Brethren, and to the flocks committed to your care, as a pledge of heavenly blessings and in token of Our fatherly goodwill, Our Apostolic Benediction.
Given at St. Peter's, Rome, on the 9th day of April, Easter Sunday, in the year 1944, the sixth of Our Pontificate.