Orthodox vs Catholic: How the Two Churches Differ and Why They Split

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For about a thousand years the Catholic and Eastern Orthodox churches were one communion, and to this day they share the same seven sacraments, bishops in apostolic succession and the first seven councils. The break between them is usually dated to 1054, and they parted chiefly over two things, the authority of the Pope and the words “and the Son” in the Creed.

Most of what else divides them is smaller, such as purgatory, the Immaculate Conception, married priests, the bread used at Communion and the date of Easter. Yet the two churches still cannot kneel at one altar. The Catholic Church says the communion between them “lacks little to attain the fullness that would permit a common celebration of the Lord’s Eucharist.” The Orthodox Church does not share Communion with Catholics, because it sees shared Communion as what full unity brings, and not as a step on the way to it. So both are still waiting on the prayer Jesus prayed, “that they may all be one” (John 17:21).

To see what Catholics teach beside what Orthodox Christians teach on 55 questions, open our free tool, Compare Christian Denominations.

Where Catholics and Eastern Orthodox Christians differ

Each answer is quoted from the church’s own documents or from one of our articles.

The Holy Spirit's origin

Catholic

The Latin tradition of the Creed confesses that the Spirit "proceeds from the Father and the Son (filioque)".

From Catechism of the Catholic Church, 246

Eastern Orthodox

Orthodox doctrine confesses that God the Father is the eternal origin and source of the Spirit, just as He is the source of the Son.

From The Orthodox Faith (OCA), Vol. I, The Symbol of Faith: The Holy Spirit

Salvation

Catholic

Justification is conferred in Baptism, the sacrament of faith. It conforms us to the righteousness of God, who makes us inwardly just by the power of his mercy.

From Catechism of the Catholic Church, 1992

Eastern Orthodox

Man was created with the potential to be a “partaker of the divine nature,” to refer to the Apostle Peter once more (2 Pet 1.4). It is this participation in divinity, called theosis (which literally means deification or divinization) in Orthodox theology, that the ascension of Christ has fulfilled for humanity.

From The Orthodox Faith (OCA), Vol. I, The Symbol of Faith: Ascension

Original sin

Catholic

The account of the fall in Genesis 3 uses figurative language, but affirms a primeval event, a deed that took place at the beginning of the history of man. Revelation gives us the certainty of faith that the whole of human history is marked by the original fault freely committed by our first parents.

From Catechism of the Catholic Church, 390

Eastern Orthodox

Concerning the original—or “first”—sin, that commited by Adam and Eve, Orthodoxy believes that, while everyone bears the consequences of the first sin, the foremost of which is death, only Adam and Eve are guilty of that sin.

From OCA Questions & Answers: Original Sin

Communion bread and wine

Catholic

According to the ancient tradition of the Latin Church, the priest is to use unleavened bread in the eucharistic celebration whenever he offers it.

From Code of Canon Law, canon 926

Eastern Orthodox

Actually, leavened bread has always been used in the Eastern Church. In fact, at one point in time, a great controversy raged over the fact that in the Eastern Church leavened bread was used, while in the Christian West unleavened bread was the norm.

From OCA Questions & Answers: Leavened Bread vs. Unleavened

Leadership

Catholic

The Pope, Bishop of Rome and Peter's successor, "is the perpetual and visible source and foundation of the unity both of the bishops and of the whole company of the faithful."

From Catechism of the Catholic Church, 882

Eastern Orthodox

The Orthodox Church as a whole is the unity of what are called local autocephalous or autonomous churches. These words mean simply that these churches govern themselves, electing their own bishops and organizing their own lives.

From OCA Questions & Answers: How is the Orthodox Church organized

Who may be ordained

Catholic

"Only a baptized man (vir) validly receives sacred ordination." The Lord Jesus chose men (viri) to form the college of the twelve apostles, and the apostles did the same when they chose collaborators to succeed them in their ministry.

From Catechism of the Catholic Church, 1577

Eastern Orthodox

In the Orthodox Church a married man may be ordained to the priesthood. His marriage, however, must be the first for both him and his wife, and he may not remarry and continue in his ministry if his wife should die. If a single man is ordained, he may not marry and retain his service.

From The Orthodox Faith (OCA), Vol. II, The Sacraments: Holy Orders

Purgatory

Catholic

All who die in God's grace and friendship, but still imperfectly purified, are indeed assured of their eternal salvation; but after death they undergo purification, so as to achieve the holiness necessary to enter the joy of heaven.

From Catechism of the Catholic Church, 1030

Eastern Orthodox

The Orthodox Church does not accept the teaching on purgatory that developed in more recent times in Roman Catholicism.

From OCA Questions & Answers: Sin

Remarriage

Catholic

The Church maintains that a new union cannot be recognized as valid, if the first marriage was. If the divorced are remarried civilly, they find themselves in a situation that objectively contravenes God's law.

From Catechism of the Catholic Church, 1650

Eastern Orthodox

The Church will permit up to, but not more than, three marriages for any Orthodox Christian. If both partners are entering a second or third marriage, another form of the marriage ceremony is conducted, much more subdued and penitential in character.

From Rev. Stanley S. Harakas, The Stand of the Orthodox Church on Controversial Issues (Greek Orthodox Archdiocese of America; hosted by the American Carpatho-Russian Orthodox Diocese)

See all 55 answers for these two churches

No, the Greek Orthodox Church is not part of the Catholic Church, and like the Russian Orthodox Church and the other Eastern Orthodox churches, it is not in communion with the Pope. It belongs to a family of self-governing Orthodox churches, and the senior bishop of that family is the Ecumenical Patriarch of Constantinople.

The Orthodox call their own church catholic as well, and when they say the Creed, they end with belief “in one, holy, catholic and apostolic Church.” The Orthodox writer Thomas Hopko explains that “the word catholic means full, complete, whole, with nothing lacking.” So an Orthodox Christian is catholic in that sense of the word without being Roman Catholic.

Several churches whose worship is Byzantine carry the name “Greek Catholic,” such as the Ukrainian Greek Catholic Church and the Melkite Greek Catholic Church, and to a visitor their services look Orthodox. Yet they are Eastern Catholic churches, in full communion with Rome.

Neither, in any simple sense, because until the eleventh century they have one history between them. Each church regards itself as the original Church, and not as a branch that broke away. Both trace their bishops to the apostles, and both hold the councils of the first millennium. In 1965 the Pope and the Patriarch looked back together to the “full communion of faith, fraternal accord and sacramental life which existed among them during the first thousand years of the life of the Church.”

The word “Orthodox” is sometimes used for a second family of churches as well, the Oriental Orthodox, among them the Coptic, Ethiopian and Armenian churches. They separated from both Rome and Constantinople after the Council of Chalcedon in 451, over how to describe Christ’s divine and human natures. Pew Research counts them as about 20 percent of the nearly 260 million Orthodox Christians in the world, which leaves the Eastern Orthodox at about 80 percent, or roughly 200 million.

They split over two questions that had been building between East and West for centuries. One was how much authority the bishop of Rome holds over the other churches, and the other was whether the West could add words to the Creed without the East.

The year usually given is 1054, when the legates of Rome, led by Cardinal Humbert, excommunicated Patriarch Michael Cerularius of Constantinople. The patriarch and his synod answered with an excommunication of their own. When Pope Paul VI and Patriarch Athenagoras I lifted those sentences in 1965, they noted that the censures of 1054 had been “directed … against the persons concerned and not the Churches.” The final break between the churches came gradually, and what happened in the centuries after hardened it.

In 1204 crusaders from the West sacked Constantinople, and the Orthodox have not forgotten it. In the words of the Orthodox Church in America, the city “was brutally sacked during the first three days of Holy Week.” Nearly eight centuries later, in Athens in 2001, Pope John Paul II spoke of it for the Catholic side: “The fact that they were Latin Christians fills Catholics with deep regret.”

Reunion was agreed at the council of Lyons in 1274, and again at Florence in 1439, and neither reunion lasted. Florence asked the Greeks to accept papal authority, the filioque and purgatory, and the Orthodox Church rejected it. Then the Catholic Church defined Mary’s Immaculate Conception in 1854 and papal infallibility in 1870, and so added two more doctrines that the Orthodox do not accept.

The difference that matters most is over the Pope, whose office Catholics ground in Christ’s words to Peter, “you are Peter, and on this rock I will build my church, and the gates of hell shall not prevail against it” (Matthew 16:18). The Catholic Church teaches that the Pope, as the successor of Peter, “has full, supreme, and universal power over the whole Church, a power which he can always exercise unhindered.” In 1870 the First Vatican Council defined that the Pope is infallible when he defines a doctrine of faith or morals for the whole Church.

The Orthodox Church is governed instead by councils of bishops, and it is a family of churches. Fourteen of them are recognized by all the others as autocephalous, which means self-governing. They are the ancient patriarchates of Constantinople, Alexandria, Antioch and Jerusalem, then the patriarchates of Russia, Serbia, Romania, Bulgaria and Georgia, and then the churches of Cyprus, Greece, Poland, Albania, and the Czech Lands and Slovakia.

Two more churches are recognized by some of the others but not by all. The Orthodox Church in America received its autocephaly from the Russian Church in 1970, and some patriarchates do not recognize it, though they stay in communion with it. The Orthodox Church of Ukraine received its autocephaly from Constantinople in January 2019. Alexandria and Greece recognize it, and Serbia and Poland are among the churches that reject it.

First among the bishops of all these churches is the Ecumenical Patriarch, currently Bartholomew I, who holds what the Orthodox call “a primacy of honor.” He convenes the councils of the whole Orthodox Church and presides over them, but each church governs itself through its own synod of bishops. As the Orthodox Church in America puts it, “Orthodoxy does not believe in the infallibility of the Pope of Rome, nor of any other individual.”

The Nicene Creed of 381 says that the Holy Spirit proceeds from the Father, and in that it echoes Jesus’ own words about “the Spirit of truth, who proceeds from the Father” (John 15:26). Later the Latin churches added the word filioque, “and the Son.” The Catholic Church’s own Catechism notes that the phrase “does not appear in the Creed confessed in 381,” that it came into the Latin liturgy between the eighth and eleventh centuries, and that it remains “a point of disagreement with the Orthodox Churches.”

Catholic teaching sees the two traditions as a “legitimate complementarity,” in which the East stresses that the Father is the first source of the Spirit and the West stresses the unity of the Father and the Son. The Orthodox object both to the doctrine and to the way it was added. Hopko calls the filioque “a doctrinal addition unacceptable to Orthodoxy since it is both unscriptural and inconsistent with the Orthodox vision of God.” As for the way it was added, the Orthodox say that the West changed, on its own, a creed agreed by councils of the whole Church.

Both churches pray for the dead, but they do not describe what happens after death in the same way. The Catholic Church teaches that those who die in God’s friendship “but still imperfectly purified” are “assured of their eternal salvation” and are purified after death, and it calls this final purification purgatory. The Orthodox Church does not accept purgatory as a state between heaven and hell.

Both churches call Mary the Mother of God and honor her as ever-virgin. The Catholic Church also teaches, as a dogma Pius IX defined in 1854, that from the first moment of her conception Mary was “preserved immune from all stain of original sin.” The Orthodox reject the Immaculate Conception, but they teach that “Mary is without personal sins.” Their objection rests partly on a different view of original sin, for the Orthodox hold that humans inherit the consequences of Adam’s sin but not its guilt.

At the end of Mary’s life, Catholics speak of her Assumption, when she was “taken up body and soul into heavenly glory.” The Orthodox keep the feast of her Dormition, her falling asleep, on 15 August, and they teach that Mary “died as all people die” and was raised by her Son.

When they speak of salvation, the two churches draw on the same sources. Orthodox teaching describes the Christian life as theosis, the “deification” of man by the grace of God, and it points to the promise that believers “may become partakers of the divine nature” (2 Peter 1:4). The Catholic Catechism quotes the same verse, and with it the Church Fathers who wrote that “the Son of God became man so that we might become God.”

Both churches allow married priests, though in the Latin Church priests are “normally chosen from among men of faith who live a celibate life.” In the Eastern churches, as the Catechism itself notes, “married men can be ordained as deacons and priests,” while “bishops are chosen solely from among celibates.” In both churches a man who is already ordained may not marry.

At the Eucharist the Latin Church uses unleavened bread, “according to the ancient tradition of the Latin Church,” and the Orthodox Church has always used leavened bread. The difference once caused a bitter controversy between East and West.

Chrismation is the Eastern name for confirmation, and an Orthodox infant receives it in the same service as baptism and Communion. In the Latin Church a child receives Communion for the first time after reaching the age of reason.

Almost all the Orthodox churches calculate the date of Orthodox Easter, which they call Pascha, by the older Julian calendar, and that includes the churches that use the newer calendar for the fixed feasts. The one exception is the Finnish Orthodox Church, which has dated Pascha by the Gregorian calendar since 1923. So Orthodox and Western Easter sometimes fall on the same Sunday and sometimes as much as five weeks apart. In 2025 they fell together, and Pope Leo XIV and Patriarch Bartholomew said they wanted to keep “exploring a possible solution for celebrating together the Feast of Feasts every year.”

The Catholic Church is made up of 24 self-governing churches, and only one of them is the Latin Church. The other 23 are the Eastern Catholic churches, among them the Ukrainian Greek Catholic Church, the Maronite Church of Lebanon and the Syro-Malabar Church of India. Many of them share the Byzantine liturgy of the Orthodox and ordain married men as priests, and yet they are in full communion with the Pope. The Second Vatican Council declared that the Eastern churches “have the power to govern themselves according to the disciplines proper to them.”

Ordinarily no. Catholic canon law allows it in principle, so the barrier is on the Orthodox side. Canon 844 lets Catholic ministers give the sacraments of penance, the Eucharist and anointing to members of the Eastern churches “if they seek such on their own accord and are properly disposed.” It also lets Catholics who cannot reach a Catholic priest receive those sacraments from ministers of churches in which they are valid, “whenever necessity requires it or true spiritual advantage suggests it.” The Catholic Church recognizes Orthodox sacraments as true sacraments.

The Orthodox Church does not offer Communion to Catholics, and it does not allow its own members to receive Communion in Catholic churches. The Orthodox Church in America gives the reason: “The Eucharist is the result of unity, not the means by which unity is achieved.” To receive in a church to which one does not belong, it adds, “would imply a unity that in fact does not yet exist.”

Their leaders are, slowly, but most Orthodox believers are less sure. In 1965, when Paul VI and Athenagoras I lifted the sentences of 1054, they declared that they “commit these excommunications to oblivion,” and in the same declaration they admitted that the gesture was “not sufficient to end both old and more recent differences.”

The joint commission for theological dialogue between the two churches first met on Rhodes in 1980. At Ravenna in 2007 this official commission agreed that in the undivided Church, Rome “occupied the first place” and its bishop was “the protos among the patriarchs.” It added that the two churches disagree about what powers that first place carried. The Ravenna document on primacy is the commission’s own work, and in its own words it “should not be understood as an official declaration of the Church’s teaching.”

In November 2025 Pope Leo XIV and Patriarch Bartholomew marked the 1,700th anniversary of the Council of Nicaea together at İznik, the ancient Nicaea. The next day, in Istanbul, they signed a joint declaration that looks toward “the hoped-for restoration of full communion between our sister Churches.”

Support among ordinary Orthodox Christians is weak. In a Pew survey of Central and Eastern Europe in 2015–2016, the view that the churches should reunite was a minority position in most countries. In Russia only 17 percent of Orthodox Christians wanted communion with the Catholic Church, and Romania, at 62 percent, was the only country where a majority were in favor.

When Catholic leaders speak of the Orthodox churches, they call them sister churches, and Patriarch Bartholomew signed the 2025 declaration in those same terms. Other Orthodox reject the idea. One answer on the Orthodox Church in America’s site says that Orthodoxy “sees herself as the fullness of the Church, not the ‘other half’ of the Church,” while granting that “there are some Orthodox who would perhaps ascribe to these notions.” The 2025 declaration asks the members of both churches to seek the fulfilment of Jesus’ prayer “that they may all be one” (John 17:21).

The Protestant churches came out of the Western, Catholic side of the split in the sixteenth century, in a break of their own with Rome. Like the Orthodox, they reject the Pope’s authority, and the Westminster Confession of the Presbyterian and Reformed churches says the Pope cannot “in any sense, be head” of the Church. Most Protestant churches kept the Western Creed with the filioque, as Catholics did, and the same confession says the Holy Spirit is “eternally proceeding from the Father and the Son.” Unlike both, most Protestants reject purgatory and do not pray to the saints.

East and West have been apart for nearly a thousand years, and in the sixteenth century the West divided again. The prayer Jesus prayed for all of us is older than every one of these quarrels: “that they may all be one” (John 17:21).

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