Pope Leo XIV and Ecumenical Patriarch Bartholomew

On November 29, during Pope Leo XIV’s trip to Turkey, he and Ecumenical Patriarch Barthelomew signed a Joint Declaration calling for ecumenical efforts toward unity between all Christians. The Holy Father’s trip to Turkey also included an ecumenical service, attended by numerous representatives of the various Christian traditions, to commemorate the First Council of Nicaea, which met over the summer of AD 325, and formulated the Creed that is professed by all Christian traditions (with some important additions made by the First Council of Constantinople in AD 381 – hence the Creed is formally called the Niceno-Constantinopalitan Creed, but most just call it the Nicene Creed).

This is only the most recent iteration of attempts to create closer ties between Rome and Constantinople (now Istanbul), over which Bartholomew reigns, representing the Orthodox tradition of Eastern Christianity. Indeed, Leo and Bartholomew’s declaration makes mention of the meeting between Pope St. Paul VI and Ecumenical Patriarch that took place sixty years ago in 1965. It was the first meeting between a pope and ecumenical patriarch since 1438. At that meeting, which took place on the Mount of Olives in Jerusalem, Paul and Athenagoras prayed together, exchanged the kiss of peace, and promulgated their own Joint Declaration, which announced the lifting of the mutual excommunications imposed in 1054 and, similarly to Leo and Bartholomew’s, called for efforts to achieve shared communion again between Catholics and Orthodox Christians.

Shared communion means inter-communion. That means that Catholics may receive Holy Communion at an Orthodox Divine Liturgy, and Orthodox may received Holy Commuion at a Catholic Mass. Currently, Catholics are not allowed to receive Holy Communion at an Orthodox Divine Liturgy, and Orthodox are strongly encouraged by their own tradition not to receive Holy Communion at a Catholic Mass. Intructions of the U. S. Catholic Bishop’s Conference Guidelines for the Reception of Communion states:

“Members of the Orthodox churches, the Assyrian Church of the East, and the Polish National Catholic Church are urged to respect the discipline of their own churches. According to Roman Catholic discipline, the Code of Canon Law does not object to the reception of Commuion by Christians in these churches. (canon 884 # 3).”

So, technically, Orthodox Christians are welcome to receive Holy Communion at a Catholic Mass, but they are encouraged to follow the disciplines of the Orthodox churches, which discourages them doing so. Catholics are not permitted to receive Holy Communion at an Orthodox Divine Liturgy according to the disciplines of the Orthodox churches, not the Catholic Church, though the Catholic Church would certainly encourage Catholics who attend an Orthodox Divine Liturgy to respect the Orthodox discipline. Orthodox churches have a tradition of offering a blessing and blessed bread, not the Body and Blood of Christ, to visitors to their liturgies. Many Catholic parishes have adopted, in recent years, the practice of inviting non-Catholics, or those not receiving Holy Communion for any reason, to come forward with their arms crossed across their chests to receive a blessing.

I do want to acknowledge the progress made in ecumenical relations between the Catholic and Orthodox churches. While as recent as the 1950s, an Orthodox ecumenical patriarch would never have entertained the idea of attending the investiture ceremony of a Catholic pope, today it would be unheard of that he would not attend. Catholics and Orthodox regularly pray together in ecumenical services, acknowledging the many teachings their churches hold in common. There are many shared saints between the Catholic and Orthodox churches, including St. Athanasius of Alexandria, the hero of Nicean Christianity, who upheld the orthodox Nicene Creed even while many of his Eastern brother bishops embraced the Arian heresy, and even while being opposed by bishops and emperors alike, and even suffering five exiles from his See over the course of his reign. Pope Francis added to the Roman martyrology, a list of Christian martyrs recognized as saints by the Catholic Church, the twenty-one Coptic Orthodox Christians who were murdered by ISIS in Libya in 2015. The work of the Joint International Commission for the Theological Dialogue between the Catholic Church and the Orthodox Church was acknowledged in Leo and Bartholomew’s Declaration, and their work continues.

However, progress notwithstanding, there are many obstacles to communion between the Catholic and Orthodox churches. Here are my thoughts on the matter. These are my thoughts alone, and do not represent or reflect any official communications between the Catholic and Orthodox churches, as if anything I say could!

Major obstacles to Communion between the Catholic and Orthodox churches, in no particular order except the last two:

1. The date for Easter. To sum up simply, Catholic and Orthodox Christians, after centuries of celebrating Easter on the same Sunday, have been celebrating Easter on different dates since 1582, when the Catholic Church adopted the Gregorian calendar and adapted everything accordingly, while the Orthodox Church continued to hold to the Julian calendar in setting the date for Easter. Earlier this year, the rare occurance of both churches celebrating Easter on the same Sunday (because that’s how both calendars set the date) sparked another surge of interest in resolving this seemingly easily resolved issue. There are two solutions, as I see it. Either the Orthodox Church gets on board with the rest of the world in adopting the Gregorian calendar (they already do for administrative and communication reasons), or both churches decide it’s not a big deal for the purpose of communion, and each Church keeps its own tradition.
2. The filioque. A much more serious issue is that of the filioque. Filioque means “… and the Son” and it was added to the Nicene Creed in the Western Church over the course of at least the sixth to the eleventh century to defend the faith against the remnants of Arianism in the West. It was not accepted by the entire Western Church until Pope Benedict VIII officially added it to the recitation of the Creed in Rome in 1014. The Eastern Church, however, rejected the addition, both on the grounds that it was an unauthorized addition (having been added by the pope and not by a Church Council), and that it was not theologically orthodox. The Orthodox Church believes in the Monarchy of the Father, that only the Father is the “principle without principle” and the origin of all divinity. The Catholic Church regards this as making the Son and Spirit subordinate to the Father and, as such, not fully divine. There’s no question that the great majority of Church Fathers, both East and West, held that either the Spirit proceeds “from the Father and the Son” or “from the Father through the Son.” Also, the East holds that the Spirit is the “Spirit of the Son.” Eyebrows were raised when Pope Leo, in his apostolic letter It Unitate Fidei, promulgated in November, 2025 in anticipation of his visit, included the text of the Nicene Creed without the filioque, and again when, during the ecumencial prayer service mentioned above, the Creed was professed also without the filioque. There has been talk that Leo is considering dropping the filioque from the Western version of the Creed, though I’m not able to find any documents that confirm that. It is true that the Eastern Catholic Churches (ie: the Melkite Catholic Church, the Coptic Catholic Church, the Ruthenian Catholic Church, etc.) are not obliged by Rome to include the filioque in their recitation of the Creed and, as far as I know, most don’t. This provision was granted to those Eastern Catholic Churches who were reconciled with Rome by the Union of Brest in 1595/96. This is not a simple matter, or one that could be rectified by the West simply dropping the filioque. There are genuine theological differences on the Holy Trinity between East and West, and the Orthodox Church is not likely to be lulled into dropping their concerns by the Catholic Church dropping the filioque. At the same time, dropping the filioque would likely cause a great deal of confusion among a great number of Catholics. A thousand or more years of tradition and practice are not easily swept aside. I don’t know if they even can be.
3. Papal primacy. This is, in the minds of many, the real obstacle to any reconciliation between Catholic and Orthodox churches. For centuries, the Orthodox churches have rejected the primacy of the Bishop of Rome. Now, as far as Rome is concerned, the primacy is a settled matter. Jesus called St. Peter the Rock on which He would build His Church and gave to St. Peter, and to him alone, the keys of the kingdom. Peter was first Bishop of Antioch and then moved to Rome, where he was the first Bishop of Rome and, thus, the first pope. That is settled Catholic history and Catholic doctrine. As pope, Peter held primacy over the entire Church. That primacy was passed on to his successors and it was practiced by his successors. I won’t go in to the evidence that the early Church acknowledged the primacy of Peter, but it’s significant. Even still, the Orthodox churches regard the Bishop of Rome as merely “first among equals.” In other words, he is recognized as having primacy in honor, but not in supreme authority or universal jurisdiction. In authority, he is not exactly one bishop among many, for what the Bishop of Rome says, for instance, certainly carries more weight than, say, the Bishop of Charleston, SC. But his authority is not that of one who closes all matters of doctrinal or practical dispute for the entire Church, and he is certainly not infallible. Observers made much of Pope Benedict XVI dropping the title “Patriarch of the West” in 2006 as an official title of the pope (though it was reinstated in 2024 as an historical honorific). Benedict did so for reasons of clarity and ecumenism, but not much came of it. Suffice it to say that I don’t see any pope, even Leo XIV, surrendering his authority as Supreme Pontiff any time soon, even in hopes it might move the Orthodox toward reconciliation. Even, of course, if any pope could surrender such authority. For the supremacy of the pope is a dogma of the Church supported by centuries of theology and practice. Even popes must submit to the “rich deposit of faith” given to us from the apostles. The supremacy of Peter and his successors is certainly part of that rich deposit, at least from a Catholic perspective. Giving up such would constitute a surrender of unparalleled proportions and significance. It would cast doubt on pretty much the entire deposit of faith the West has professed from the beginning. On the other hand, adopting papal supremacy would be much the same for Orthodox Christians. I don’t see a resolution on this one. Even in the unlikely scenario of the Ecumenical Patriach submitting to Rome as having supreme and universal authority, there is one huge obstacle that would still stand in the way of full communion. And that is …
4. The Russian Orthodox Church. Upwards of half of all Orthodox Christians in the world are Russian Orthodox, or about 110 million Christians. So it constitutes far and away the largest of the Eastern churches. The relationship between the Catholic Church and the Russian Orthodox Church is not a strong one. There’s not a lot of love lost between the two, at least from the Russian point of view. Catholic ecumenists, including popes (?), have, perhaps, been niave in neglecting the role of the Russian church in their efforts to bridge the gap between Catholic and Orthodox. It’s understandable that efforts at ecumenism have mostly meant reaching out to the ecumenical patriarch in Constantinople. He is, after all, the ecumencial patriarch and, in that role, stands as first among equals in the Orthodox role (so long as division with Rome continues). But in reality, it is the Patriarch of Moscow, emodied today in the person of Patriarch Kirill, that holds most of the cards in any journey toward reconciliation. And, historically, the patriarchs of Moscow have communicated little interest in the effort. The bottom line is, Moscow regards Rome as being in heresy. As such, Moscow has little regard for efforts toward reconciliation absent Rome repenting of her false teaching and adopting Orthodox doctrine (and probably practice, too). That doesn’t give much hope for a rapproachment. It is said, too, that Patriarch Kirill adheres to what is called a “Third Rome” ideology, where Rome was regarded as the “First Rome,” Constantinople the “Second Rome,” and Moscow now the “Third Rome,” a position of authority it will hold until the Second Coming. If that’s the case, then the Russian Church probably has little incentive for reconciliation with churches it regards as inferior. For instance, representatives of many of the Orthodox churches participated in the ecumenical prayer service in Turkey this year with Pope Leo and Patriarch Bartholomew. No Russian Orthodox representative was present. Part of that was not merely because of disputes with the Catholic Church, but with the ongoing schism between Moscow and Constantinople, and Moscow and Alexandria. The fued between these Orthodox churches is rooted in the ecumenical patriarch and the Greek Orthodox patriarch in Alexandria recognizing the Orthodox Church of Ukraine. Because of the invasion of Ukraine by Russia, and the defense of such by Patriarch Kirill, going so far as to call the conflict a “holy war,” part of the Ukrainian Orthodox Church – Moscow Patriarchate seceded and formed two distinct churches: the Ukrainian Autocephalus Orthodox Church and the Ukrainian Orthodox Church – Kyiv Patriarchate. The Russian Orthodox Church does not recognize these two, but regards them as rogue churches in schism from the Moscow. However, in 2018, Ecumenical Patriarch Bartholomew recognized both churches as autocephalous (meaning self-ruling), as did the Greek Orthodox Patriarch of Alexandria, Theodore II. As a result, Moscow broke communion with both patriarchs. I’ve no idea where other Orthodox churches stand on the split between the Russian and Greek Orthodox Churches, but the fact that so many representatives of the various Orthodox churches were willing to travel to Turkey and participate in the ecumenical prayer service with Leo and Bartholomew gives more than a hint. To be honest, it may be the schism between Moscow and Constantinople will free up Constantinople to be more open to Rome, given that Moscow is somewhat out of the picture for now.

There certainly are other, smaller obstacles in the way of reconciliation between Rome and Constantinople. For now, I rejoice in the mutual respect and recognition shown between our two Churches, and I’m glad that Pope Leo is reaching out, and that Patriarch Bartholomew is reciprocating. There is enough of the devil to fight in our relations with the secular world. We don’t need to be fighting each other. That doesn’t mean that the differences aren’t real and relevant. It does mean that, united in Christ, we ought to be able to see past some of those differences for the sake of unity in Christ. Realistically speaking, however, I don’t see any prospect for true, full communion any time in the near future. And, for both Eastern and Western Christianity, “the near future” translates into at least one or two centuries.