A Note from the Vatican on the Expression ‘Sister Churches’

A Note from the Vatican on the Expression ‘Sister Churches’

This is the official, Vatican perspective on not only ecumenical efforts in general, but also the relationship between the Vatican See and the Orthodox Church.

Written under the oversight of Cardinal Joseph Ratzinger (now Pope emeritus Benedict XVI), Prefect of the Congregation for the Doctrine of the Faith, this document was approved by Pope John Paul II (June 9, 2000).

Highlighted below is an ecclesiological perspective often absent in careless, ecumenical discussions (both East and West), and is a helpful corrective to radical ‘ecumenists’ who would deny the basic foundations of Christianity; that is, that Christ has established one holy, catholic, and apostolic Church, and that the gates of Hades will never divide it (Matt. 16:18).

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Note on the Expression ‘Sister Churches’

1. The expression ‘sister Churches’ occurs often in ecumenical dialogue, above all, in the dialogue between Catholics and Orthodox, and is the object of continuing study by both parties. While there is certainly a legitimate use of this expression, an ambiguous use has become prevalent in contemporary writings on ecumenism. In conformity with the teaching of the Second Vatican Council and the post-conciliar Papal Magisterium, it is therefore appropriate to recall the correct and proper use of this expression. It is helpful to begin with a brief historical outline.

I. The origin and development of the expression

2. The expression sister Churches does not appear as such in the New Testament; however, there are numerous indications of the sisterly relations which existed among the local Churches of Christian antiquity. The New Testament passage which most explicitly reflects this awareness is the final sentence of the Second Letter of John: “The sons of your elect sister send you their greetings” (2 Jn 13). These are greetings sent by one ecclesial community to another; the community which sends the greetings calls itself the sister of the other.

3. In Christian literature, the expression begins to be used in the East when, from the fifth century, the idea of the Pentarchy gained ground, according to which there are five Patriarchs at the head of the Church, with the Church of Rome having the first place among these patriarchal sister Churches. In this connection, however, it needs to be noted that no Roman Pontiff ever recognized this equalization of the sees or accepted that only a primacy of honour be accorded to the See of Rome. It should be noted too that this patriarchal structure typical of the East never developed in the West.

As is well known, the divergences between Rome and Constantinople led, in later centuries, to mutual excommunications with “consequences which, as far as we can judge, went beyond what was intended and foreseen by their authors, whose censures concerned the persons mentioned and not the Churches, and who did not intend to break the ecclesial communion between the sees of Rome and Constantinople.”1

4. The expression appears again in two letters of the Metropolitan Nicetas of Nicodemia (in the year 1136) and the Patriarch John X Camaterus (in office from 1198 to 1206), in which they protested that Rome, by presenting herself as mother and teacher, would annul their authority. In their view, Rome is only the first among sisters of equal dignity.

5. In recent times, the Orthodox Patriarch of Constantinople, Athenagoras I, was the first to once again use the expression sister Churches. In welcoming the fraternal gestures and the call to unity addressed to him by John XXIII, he often expressed in his letters the hope of seeing the unity between the sister Churches re-established in the near future.

6. The Second Vatican Council adopted the expression sister Churches to describe the relationship between particular Churches: “in the East there flourish many particular local Churches; among them the Patriarchal Churches hold first place, and of these, many glory in taking their origins from the apostles themselves. Therefore, there prevailed and still prevails among Eastern Christians an eager desire to perpetuate in a communion of faith and charity those family ties which ought to exist between local Churches, as between sisters.”2

7. The first papal document in which the term sisters is applied to the Churches is the Apostolic Brief Anno ineunte of Paul VI to the Patriarch Athenagoras I. After having indicated his willingness to do everything possible to “re-establish full communion between the Church of the West and that of the East,” the Pope asked: “Since this mystery of divine love is at work in every local Church, is not this the reason for the traditional expression ‘sister Churches,’ which the Churches of various places used for one another? For centuries our Churches lived in this way like sisters, celebrating together the ecumenical councils which defended the deposit of faith against all corruption. Now, after a long period of division and mutual misunderstanding, the Lord, in spite of the obstacles which arose between us in the past, gives us the possibility of rediscovering ourselves as sister Churches.”3

8. The expression has been used often by John Paul II in numerous addresses and documents; the principal ones, in chronological order, are the following:

In the Encyclical Slavorum Apostoli: “For us they [Cyril and Methodius] are the champions and also the patrons of the ecumenical endeavor of the sister Churches of East and West, for the rediscovery through prayer and dialogue of visible unity in perfect and total communion.”4

In a Letter from 1991 to the Bishops of Europe: “Hence, with these Churches [the Orthodox Churches] relations are to be fostered as between sister Churches, to use the expression of Pope Paul VI in his Brief to the Patriarch of Constantinople, Athenagoras I.”5

In the Encyclical Ut unum sint, the theme is developed above all in number 56 which begins in this way: “Following the Second Vatican Council and in the light of earlier tradition, it has again become usual to refer to the particular or local Churches gathered around their Bishop as ‘sister Churches.’ In addition, the lifting of the mutual excommunications, by eliminating a painful canonical and psychological obstacle, was a very significant step on the way toward full communion.” This section concludes by expressing the wish that the “traditional designation of ‘sister Churches’ should ever accompany us along this path.” The topic is taken up again in number 60 of the Encyclical: “More recently, the joint international commission took a significant step forward with regard to the very sensitive question of the method to be followed in re-establishing full communion between the Catholic Church and the Orthodox Church, an issue which has frequently embittered relations between Catholics and Orthodox. The commission has laid the doctrinal foundations for a positive solution to this problem on the basis of the doctrine of sister Churches.”6

II. Directives on the use of the expression

9. The historical references presented in the preceding paragraphs illustrate the significance which the expression sister Churches has assumed in the ecumenical dialogue. This makes the correct theological use of the term even more important.

10. In fact, in the proper sense, sister Churches are exclusively particular Churches (or groupings of particular Churches; for example, the Patriarchates or Metropolitan provinces) among themselves.7 It must always be clear, when the expression sister Churches is used in this proper sense, that the one, holy, catholic and apostolic Universal Church is not sister but mother of all the particular Churches.8

11. One may also speak of sister Churches, in a proper sense, in reference to particular Catholic and non-catholic Churches; thus the particular Church of Rome can also be called the sister of all other particular Churches. However, as recalled above, one cannot properly say that the Catholic Church is the sister of a particular Church or group of Churches. This is not merely a question of terminology, but above all of respecting a basic truth of the Catholic faith: that of the unicity of the Church of Jesus Christ. In fact, there is but a single Church,9 and therefore the plural term Churches can refer only to particular Churches.

Consequently, one should avoid, as a source of misunderstanding and theological confusion, the use of formulations such as “our two Churches,” which, if applied to the Catholic Church and the totality of Orthodox Churches (or a single Orthodox Church), imply a plurality not merely on the level of particular Churches, but also on the level of the one, holy, catholic and apostolic Church confessed in the Creed, whose real existence is thus obscured.

12. Finally, it must also be borne in mind that the expression sister Churches in the proper sense, as attested by the common Tradition of East and West, may only be used for those ecclesial communities that have preserved a valid Episcopate and Eucharist.

Rome, from the Offices of the Congregation for the Doctrine of the Faith, June 30, 2000, the Solemnity of the Sacred Heart of Jesus.

+ Joseph Card. Ratzinger, Prefect

+ Tarcisio Bertone, S.D.B., Archbishop Emeritus of Vercelli & Secretary

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Show 9 footnotes

  1. Paul VI and Athenagoras I, Joint Declaration Pénétrés de reconnaissance (7-12-65), 3: AAS 58 (1966), 20. The excommunications were mutually lifted in 1965: “Pope Paul VI and Patriarch Athenagoras I in his Synod … declare by mutual agreement … to regret and to remove from memory and from the midst of the Church the sentences of excommunication” (ibid.,4); cf. also Paul VI, Apostolic Letter Ambulate in dilectione (7-12-65): AAS 58 (1966), 40-41; Athenagoras I, Patriarchal Τόμoς (7-12-65): ΤΟΜΟΣ ΑΓΑΠΗΣ Vatican-Phanar (1958-1970), 129 (Vatican Polyglot Press: Rome-Istanbul, 1971), 290-294
  2. Second Vatican Ecumenical Council, Decree Unitatis redintegratio, 14
  3. Paul VI, Apostolic Brief Anno ineunte (25-7-67): AAS 59 (1967), 852, 853
  4. John Paul II, Encyclical Letter Slavorum Apostoli (2-6-85), 27: AAS 77 (1985), 807
  5. John Paul II, Letter to the Bishops of Europe on Relations between Catholics and Orthodox in the New Situation in Central and Eastern Europe (31-5-91), 4: AAS 84 (1992), 167
  6. John Paul II, Encyclical Letter Ut unum sint (25-5-95), 56 and 60: AAS 87 (1995), 954, 955, 957
  7. cf. The texts of the Decree Unitatis redintegratio, 14, and the Apostolic Brief of Paul VI to Athenagoras I Anno ineunte, cited above in footnotes 2 and 3
  8. cf. Congregation for the Doctrine of the Faith, Letter Communionis notio (28-5-1992), 9: AAS 85 (1993), 843-844
  9. cf. Second Vatican Ecumenical Council, Dogmatic Constitution Lumen gentium, 8; Congregation for the Doctrine of the Faith, Declaration Mysterium Ecclesiae (24-6-73), 1: AAS 65 (1973), 396-398


  1. Maximus says


    Christ is risen!

    You guys are putting out some great stuff to combat ecu-mania. Basic Orthodox ecclesiology is not so basic in these times and straightforward confession is becoming a rarity. A sincere thanks to you all!

    • says

      Thanks, Maximus!

      We’re not opposed to ‘ecumenism,’ properly done. But that requires admitting that there are real differences that separate us. And also admitting that we both believe there is one, true Church, and only one of us can be her.

      I fear that most efforts on a large scale ignore this basic foundation.

  2. Misha says

    That is Rome’s perspective, and interesting I suppose. For the Orthodox, it is even more simple. The only sister Churches are Orthodox Churches such as the Church of Russia, the Church of Serbia, the Church of Greece, for example. Being that there is only one, holy, catholic and apostolic Church, that Church is the Orthodox Catholic Church or, more concisely, the Orthodox Church. Rome is outside of the Church. We should not mince words about that. It’s not a matter of apostolic succession. It’s not a matter of historical primacy. It’s simply a fact to which a number of Orthodox saints have attested and which the Church has held to be the truth for many centuries. Only in the recent past has it become fashionable, due to ecumenism, to sugarcoat the matter.

    • says

      Our perspective is largely the same, although we obviously disagree on which Church is the one, true Church. They believe it to be Rome, whereas we believe it to be the united local churches of the canonical, Chalcedonian Orthodox Church.

      Rome uses ‘sister churches’ in the same way as you’ve used it here, too: as local churches under the same Head. Except, for them, the Head is the Pope (and for us, Christ alone).

      Apostolic succession needn’t be thrown out the window. We hold to that just as faithfully as those in the West. Except for us, succession in ordination is not enough; a succession in faithfulness to the apostolic Faith is equally important. Otherwise, succession is meaningless.

      And this is why we reject Rome’s claims to catholicity and authority: they have abandoned the catholic and apostolic faith, regardless of apostolic succession.

      • Maximus says

        Perhaps you can send this post to Constantinople (with love of course) and “stir them up by way of reminder” (2 Pet. 1:13).

        May God sanctify us all by the Truth!

  3. Misha says


    Yet Rome communes Orthodox (both Eastern and Oriental). It seems more complicated for them than for us (the Roman attitude that Orthodox Churches are truly Churches, but with a defect, as opposed to the Orthodox notion that there is but one Church whose “branches”, if any, are internal. But no reason to go into it here.


    If the Phanar has not been corrected by the numerous memos sent from Athos, I don’t think much else will persuade them either.

    • says

      They do so in principle, but there’s likely not many Orthodox Christians actually communing on a regular basis at a Roman Catholic parish. After all, this would require extreme circumstances, bishops, etc., be involved.

  4. V. Rev. A. James Bernstein says

    Gabe, Christ is Risen! A very useful post. I had assumed that the Roman Catholic Church officially view us as a sister church much the same as some Orthodox spokesmen view them as a sister church. It is somewhat encouraging to me to see that they don’t officially view us as such. So it is with the 2 lung ecclesiology views presented by some prominent Orthodox spokesmen. So then, I suppose that the Roman Catholics can better appreciate the CONSISTENCY of our holding ourselves to be truly – The One Holy Catholic and Apostolic Church – being as that is what they hold of themselves.

    • says

      Fr. James,

      Truly, He is risen! Thank you for sharing your thoughts here. Like you, I find this comforting, not offensive. I would rather us speak the truth in love, than speak lies under a false pretense of love.

      Only in the truth can we ever have a meaningful dialogue, and move on towards unity in Christ—but only a unity that recognizes the existence of one, true Body of Christ.

  5. Tom Martin says

    Christ is Risen! I was probably a hair away from converting to the Roman church, but by the mercy of God none of my RC friends could answer my questions, and none of the RC chaplains at the hospital where I worked wanted to discuss it (I don’t discuss religion at work). ?????? Well, to make an extremely long story short, I was Christmated on May 4, 2013 (Holy Saturday) and prior to and after my Christmation I’ve read about the Great Schism and Ecumenism and Papal Infallibility and all that. As an Orthodox Christian, I can’t help to wonder . . . why all the talk? It ain’t never gonna happen. The Pope will never relinquish his crown, and we Orthodox will never accept the Pope as the leader of the Orthodox Church. There are other issues as well, and those issues are almost equally as separating as the Pope. I guess what I’m trying to say is that sure, I get upset when I hear or read about the “Ecumenical Movement”, but discussion of it just seems like a waste of time. Like I said — it just isn’t going to happen. Great blog.

  6. Misha says


    I won’t delve too deeply into the Pat. of Constantinople’s motives but I think there is a lot of buzz/photo-op involved. Politicians find the attention they get intoxicating and I think these types things are staged to generate the same type of buzz.

    Pat. Bartholomew received instruction at the Pontifical Institute in Rome so his notions of primacy in the Orthodox Church are quasi-papal anyway. Hard to say what he might be willing to do.

    Can’t say I really care. Moscow is viewing this as a meeting not between the RCC and the OC but between the RCC and the Church of Constantinople alone.

    • says

      You bring up an important point in that both Moscow and the Ecumenical Patriarchate fundamentally disagree on what it means for a Patriarch to have ‘primacy’ (whether he be the Pope or Ecumenical Patriarch of Constantinople).

      Until these sorts of ‘internal’ debates are settled, approaching a union with the Vatican seems a non-starter.

      Personally, I would rather we spend more time uniting with the various Oriental communions, and working out those particular issues. That would make far more logical sense to me. But I’m just one opinion. :-)

  7. Misha says

    Oh, I suppose I’m a confirmed navel-gazer. If we build up traditional Orthodoxy from within, everything else will take care of itself in time. If not, we get nowhere anyway, having lost the substance of the Truth.

    Pursuing theosis through the mysteries, prayer and service and pursuing evangelism, mostly through setting a good example and ministries to the wider community – these are the future of Orthodoxy. Ecumenism is fool’s gold, a photo op, an excuse for bishops and metropolitans, etc to be interviewed, to create buzz. Yet they yield nothing much of value.

    Our faith is well documented. Any literate person can find it explicated. If the Pope or the head of one of the “Oriental Orthodox” churches wants to convert, they know where to go. I can’t believe that they don’t know what we believe. They just refuse to accept it. Over that we have no control. However, over personal piety and community outreach we have considerable control.

    Grow the Church from within and the exterior will shrink.

  8. Gregory Manning says

    Congratulations on an excellent web site!
    Though I found this published on an Orthodox website I don’t see it getting much circulation. It’s lengthy but it seems to me well worth the read. It is, apparently, something the late Fr. Georges Florovsky wrote regarding union vs. unity with Rome and, characteristic of Fr. Florovsky, is blessed with insight(s). In contrast to his views and those expressed by others wary of the current activities of the E.P. and other like-minded folks in the ecumenical movement, I often recall Fr. Alexey Young’s book “The Rush to Embrace”.
    Again, well done.


    • says

      Thank you, and thanks for the recommendation. I will give it a look.

      I’ve always meant to read Fr. Alexey’s book, but haven’t done so yet.

  9. Mary says

    I am not quiet clear on how one concludes that this clarification indicates that Orthodox Churches are not Sister Churches?

    “10. In fact, in the proper sense, sister Churches are exclusively particular Churches (or groupings of particular Churches; for example, the Patriarchates or Metropolitan provinces) among themselves.7 It must always be clear, when the expression sister Churches is used in this proper sense, that the one, holy, catholic and apostolic Universal Church is not sister but mother of all the particular Churches.8″

    • says


      I’m not sure which part of this excerpt you have in mind, but if it’s the reference to Patriarchates or Metropolitan provinces, that’s a reference to Eastern-rite Catholic churches, which are sister churches under the Roman communion.