Rorate Caeli

Mystici Corporis at 70 - I
The true Church of Christ is the Holy, Catholic, Apostolic, Roman Church

The major encyclical of Pope Pius XII on the Church, Mystici Corporis Christi, the clearest and most incisive document on the Bride of Christ in the 20th Century, was signed on June 29, 1943, Feast of Sts. Peter and Paul, days before the bombing of Rome and the fall of the Fascist government. As war raged, Pope Pacelli felt the great need to clarify matters in the spiritual war being fought within the Church by the re-emerging Modernists, who wished once again to muddle the doctrine on the Church. In the upcoming weeks, we will celebrate this great anniversary with a special series.


In the brilliant prolixity of his writings and his allocutions, the late and beloved Sovereign Pontiff, Pope Pius XII, made important contributions to many areas within the field of Catholic doctrine. Yet one theological treatise seems to have been affected and improved more effectively than any other by what he wrote and said in his capacity as the Vicar of Jesus Christ on earth. That treatise is the tractatus de ecclesia Christi.

During the early years of the twentieth century there was more confusion and misunderstanding about the Church than about any other reality studied in the science of sacred theology. Three factors were responsible for the comparatively imperfect status of popular writing about the kingdom of God on earth. First, there was the fact that the treatise on the true Church of Jesus Christ had a history quite different from that of most of the other individual treatises within the confines of dogmatic theology.1 Second among these factors was the unfortunate misinterpretation of terminology employed in St. Robert Bellarmine's classical De ecclesia militante over the period from the sixteenth century until the nineteenth.2 The last and the most important factor was the influence of popular and superficial religious writing strongly influenced by liberal Catholicism.3

These three factors, acting together, produced a condition in which religious books by some rather influential Catholic authors tended, during the first half of the twentieth century, to speak of a kind of super-Church, a Mystical Body of Jesus Christ, in some way distinct from and superior to the visible Catholic Church over which the Bishop of Rome presides as visible head and as the Vicar on earth of Our Lord Jesus Christ. Basically, it was that condition which the late and great Sovereign Pontiff was called upon to remedy. And, by the force of his most important writings and allocutions, he fulfilled this task most admirably.

Amidst the literally thousands of entries in the official Acta of Pope Pius XII there are hundreds of documents in which he set forth teaching about the nature and the dignity of the Catholic Church as the true Church of Jesus Christ. As a result any full-scale study of the effects of Pius XII in the field of ecclesiology would have to be expressed in a rather formidable volume. Yet, among the very numerous documents which would certainly have to be scrutinized in such a work, there are a very few statements of his which had particular moment for all theologians interested in the treatise on the Church. He seemed to have a special affection for these declarations. I can think of no more effective way of honoring his beloved memory in this issue of The American Ecclesiastical Review than that of bringing together his most striking teachings about the Church he loved so much and guided so well.

Mystici Corporis Christi

The Mystici Corporis Christi and the subsequent encyclical, the Humani generis, may well go down in history as the two most important doctrinal statements issued by Pope Pius XII during the course of his long and glorious reign as Christ's Vicar on earth. Both exercised an extraordinarily powerful regulatory influence within the tractatus de ecclesia Christi.

Pope Pius XII issued the Mystici Corporis Christi on June 29, 1943. The first and the most fundamental contribution it made to Catholic thought on the Church is contained in the following sentence:
If we would define and describe this true Church of Jesus Christ — which is the One, Holy, Catholic, Apostolic Roman Church — we shall find nothing more noble, more sublime, or more divine than the expression "the Mystical Body of Jesus Christ" — an expression which springs from and is, as it were, the fair flowering of the repeated teaching of the Sacred Scriptures and the holy Fathers.4

After this strong and eminently clear declaration, there could be no shadow of excuse for any tactic tending to depict the Mystical Body of Our Lord as in any way distinct from or superior to the visible Catholic Church, the religious society over which the Vicar of Christ rules as the visible head. The expression "Mystical Body of Jesus Christ" appears in this ringing pronouncement of Pius XII as the description and even as the definition of the One, Holy, Catholic, Apostolic Roman Church. The Mystici Corporis then gives the coup de grace to the teachings that the true Church of Jesus Christ is something other than a visible or truly organized society in this world by the following pronouncement:

Hence they err in a matter of divine truth, who imagine the Church to be invisible, intangible, a something merely "pneumatological" as they say, by which many Christian communities, though they differ from each other in their profession of faith, are united by an invisible bond.5
In the same way this great encyclical letter reproves the error and confusion inherent in the writings of those Catholics who taught the existence of a twofold Church of God in this world:

For this reason We deplore and condemn the pernicious error of those who dream of an imaginary Church, a kind of society that finds its origin and growth in charity, to which, somewhat contemptuously, they oppose another, which they call juridical. But this distinction which they introduce is false: for they fail to understand that the reason which led our Divine Redeemer to give to the community of men He founded the constitution of a Society, perfect in its kind and containing all the juridical and social elements — namely, that He might perpetuate on earth the saving work of Redemption — was also the reason why He willed it to be enriched with the heavenly gifts of the Paraclete.6

Finally, Pope Pius XII, writing in the Mystici Corporis Christi, set forth the truth that the visible Catholic Church is actually the Mystical Body of Jesus Christ, the true Church of God spoken of in the Scriptures, when he brought out the fact that the members of the Catholic Church recognizable as such, or, in other words, the members of the visible Catholic Church, are the true and only members of the true Church. He wrote:

Actually only those are to be included (annumerandi) as members of the Church who have been baptized and profess the true faith, and who have not been so unfortunate as to separate themselves from the unity of the Body (neque a Corporis compage semet ipsos misere separarunt), or been excluded by legitimate authority for grave faults committed.7

There was another point magnificently clarified by the late Sovereign Pontiff in the text of the Mystici Corporis Christi. That was the teaching on the necessity of the Catholic Church for the attainment of eternal salvation. The following passage gives precious instruction on the status of those who are linked to the true Church by an unconscious or merely implicit desire or intention to enter this society.
As you know, Venerable Brethren, from the very beginning of Our Pontificate, We have committed to the protection and guidance of heaven those who do not belong to the visible Body of the Catholic Church (qui ad adspectabilem, non pertinent Catholicae Ecclesiae compagem), solemnly declaring that after the example of the Good Shepherd We desire nothing more ardently than that they may have life and have it more abundantly. Imploring the prayers of the whole Church We wish to repeat this solemn declaration in this Encyclical Letter in which We have proclaimed the praises of the "great and glorious Body of Christ," and from a heart overflowing with love We ask each and every one of them to correspond to the interior movements of grace, and to seek to withdraw from that state in which they cannot be sure of their salvation (in quo de sempiterna cuiusque propria salute securi esse non possunt). For even though by an unconscious desire and longing (inscio quodam desiderio ac voto) they have a certain relationship (ordinentur) with the Mystical Body of the Redeemer, they still remain deprived of those many heavenly gifts and helps which can only be enjoyed in the Catholic Church. Therefore may they enter into Catholic unity and, joined with Us in the one, organic Body of Jesus Christ (in una Iesu Christi Corporis compagine coniuncti), may they together with us run on to the one Head in the Society of glorious love. Persevering in prayer to the Spirit of love and truth, We wait for them with open and outstretched arms to come not to a stranger's house, but to their own, their father's home.8

There is another important item on which the Mystici Corporis Christi issues a doctrinal decision. Prior to the issuance of this encyclical Catholic theologians had debated as to whether the residential bishops of the Catholic Church derived their power of jurisdiction immediately from Our Lord or from Him through the Roman Pontiff. In this document, Pope Pius XII took occasion to speak of the Bishops' power of jurisdiction and he described it as something "which they receive directly (immediate) from the same Supreme Pontiff."9 In the edition of his Institutiones Iuris Publici Ecclesiastici which came out after the issuance of the Mystici Corporis Christi, Cardinal Ottaviani took occasion to state that this teaching, which had hitherto been considered up until this time as more probable, and even as common doctrine, must now be accepted as entirely certain by reason of the words of the Sovereign Pontiff Pius XII.10

Msgr. Joseph  Clifford Fenton 
Pope Pius XII and the Theological Treatise on the Church
(American Ecclesiastical Review, Dec. 1958 - excerpt)


1 Cf. Fenton, The Catholic Church and Salvation (Westminster, Maryland: The Newman Press, 1958), pp. 165-70.
2 Cf. ibid., pp. 171-88.
3 The tendency called "liberal Catholicism" is founded on religious indifferentism, involving opposition to the dogmas of the necessity of the true faith and of the true Church for the attainment of eternal salvation. Cf. "The Components of Liberal Catholicism," in AER, CXXXIX, 1 (July, 1958), 36-53.
4 NCWC translation, n. 13.
5 Ibid., n. 14.
6 Ibid., n. 65.
7 Ibid., n. 22.
8 Ibid., n. 103.
9 Ibid., n. 42.
10 Cf. Ottaviani, Institutiones iuris publici ecclesiastici, 3rd ed. (Typis Polyglottis Vaticanis, 1947), I, 413; and Fenton, "The Doctrinal Authority of Papal Encyclicals," in AER, CXXI, 2, 3 (Aug., Sept., 1949), 136-50; 210-20.


  1. Can some one clarify: I heard that a german priest wrote most of, if not Mystici Corporis, then Mediator Dei.
    I ask because I was convinced that encyclicals were written soley by the Pope.

  2. It is usually thought Fr. Sebastiaan Tromp, S.J., a Dutchman, wrote the first draft, as he usually assisted Pope Pacelli in theological writings. Anyway, for all ecclesiastical purposes, an Encyclical is solely by the Pope, but of course he may ask anyone to write parts or most of it, and all are revised by various dicasteries, in particular the Holy Office and its successor. When he signs it, of course, it becomes solely his own, his thinking, and his responsibility.

  3. What a great pontiff was the venerable Pius XII! Lets beg Divine Mercy that H.H. Francis emulates this worthy successor of St. Peter!

  4. At its time, the Arian heresy had an overwhelming stronghold throughout the Church. When St. Pius X condemned the heresy of modernism, it continued in the Church. Its great to know that Ven. Pius Xll recognized in 1943 that it still was a heresy strongly held to. Sadly at Vatican Council ll those who practiced this heresy, popped the ugly head of modernism out in full view. After the Council, in the name of the Council, modernism has become like the Arian heresy at its time. Modernism has become the absolute rule that all must adhere to. Or they are made to look foolish, and accused of being traditionalists who don't know what they are talking about. I am more and more being convinced that by Divine Providence, God the Holy Ghost has truly chosen the SSPX as one of His instruments to defend his Church. For God's sake they are only trying to keep the Church of Jesus Christ intact. They are opposed by only one single enemy. MODERNISM!

  5. "If we would define and describe this true Church of Jesus Christ — which is the One, Holy, Catholic, Apostolic Roman Church"

    Where does this leave the Eastern Catholic churches, which being Holy, Catholic and Apostolic, are by no means Roman?

    Or are we to understand that the Holy Catholic Apostolic Church is the Church of Christ, but not exclusively, as can be inferred from more recent documents such as Dominus Iesus?

  6. If members of the SSPX respected the teaching of Mystici Corporis they would return to the Church at once. Alas, they have developed a way of reading church documents which makes them blind to their own faults. This is why the living magisterium is so critical.

  7. Pius XII: Hence they err in a matter of divine truth, who imagine the Church to be invisible, intangible, a something merely "pneumatological" as they say, by which many Christian communities, though they differ from each other in their profession of faith, are united by an invisible bond.

    Compendium of the Catechism of the Catholic Church: 'Who Belongs to the Catholic Church?

  8. Filipe d'Avillez,

    The true Eastern Churches must be Roman. They are not Latin, which is perhaps what you are thinking of, as the Latin Church is distinct from the Eastern Churches. But they must be Roman, as Rome is the earthly center of the Faith, the Bishop of Rome is the Supreme Pontiff, and all this by Divine Decree, not happenstance.

  9. Thank you, Kathrin.

    Yes, I'm mystified when I see some post-Conciliar Eastern Catholics proudly saying they are "not Roman" Catholics... Something that would horrify any pre-Conciliar Eastern Catholic.

    Every Catholic is a Roman Catholic - not every Catholic is a member of the Latin Church or makes use of the Roman Rite (the actual one, or its funny and hippy distant cousin, the Novus Ordo), but being Catholic means being Roman.

  10. Here is a link to the Jesuit periodical Theological Studies where the subsistit in versus est debate is recounted from the real change side ( Fr. Francis A Sullivan) but he gives you the OR reference in the beginning of the Jesuit opposing him, a Fr. Becker...who held that no change took place. It is microscopic as to the draft changes at the Council and the reasoning...

  11. "Hence they err in a matter of divine truth, who imagine the Church to be invisible, intangible, a something merely "pneumatological" as they say, by which many Christian communities, though they differ from each other in their profession of faith, are united by an invisible bond."

    Did I dream when I heard many post Vatican II prelates (even possibly a pope) speaking of that "invisible Church" that goes far beyond the borders of the catholic Church?
    So they erred?...
    I am confused for the least.

  12. Filipe, if your idea is to ask questions here, and then make web gossip about us in Eastern Catholic forums, then you are asked to please never comment here again. This kind of division between Catholics is not welcome - and we love our Eastern Catholic friends and brethren.

    Now, the point is: would a specific Catholic die for his allegiance to Peter and the Roman See? If so, then he is "Roman" even if he does not wish to be called so. Strictly, each one of us in the Ecclesiastical "West" is not a "Roman" Catholic, but a Latin Catholic (in the sense that our Church is the Latin Church), but we, Latins and Easterners, become "Roman", regardless of each church or rite, because of our communion with the Bishop of Rome, through whom we are in communion with other Catholics. Does an Eastern Catholic recognize the full authority of the Bishop of Rome? Then, he is Roman, just as we Latins are, it is as simple as that. He is the Head of the College of Bishops (CCEO, Can 43: Ecclesiae Romanae Episcopus, in quo permanet munus a Domino singulariter Petro, primo Apostolorum, concessum et successoribus eius transmittendum, Collegii Episcoporum est caput, Vicarius Christi atque universae Ecclesiae his in terris Pastor, qui ideo vi muneris sui suprema, plena, immediata et universali in Ecclesia gaudet potestate ordinaria, quam semper libere exercere potest); therefore, every Catholic Church of the East also recognizes his primacy, including his primacy of power (canon 44 of the same Eastern Code), and therefore each of these Churches's members is "Roman" in this sense.

    I have only noticed this hesitancy in recognizing the "Roman" nature of Eastern Catholics in the United States, I really have no idea why.



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