What Is the Difference Between Catholics and Orthodox?

So Close, Yet Divided

To a visitor, an Orthodox Divine Liturgy and a Catholic Mass might look very different: icons and incense, chant in Greek or Slavonic, a screen of icons across the sanctuary. Yet Catholics and Orthodox share more than any other two Christian traditions.

They have been separated since the Great Schism, traditionally dated to 1054. (For the history, see What Caused the Great Schism of 1054?) Today the Catholic Church has around 1.4 billion members; the Orthodox Churches together have more than 200 million.

What Is the Orthodox Church?

The Orthodox Church is not a single organisation with one head. It is a communion of self-governing (autocephalous) Churches, such as the Ecumenical Patriarchate of Constantinople, and the Churches of Greece, Russia, Serbia, Romania, Bulgaria, Antioch and others. They share the same faith and sacraments. The Ecumenical Patriarch of Constantinople is honoured as “first among equals,” but he does not have authority over the other Churches.

The list is long.

The same seven sacraments, including the Eucharist, which both believe is truly the Body and Blood of Christ.
Apostolic succession: bishops in an unbroken line from the apostles. The Catholic Church recognises Orthodox priests, bishops and sacraments as valid (CCC 838).
The first seven ecumenical councils and the Nicene Creed.
Sacred Tradition alongside Scripture.
Deep devotion to Mary, the Mother of God, and to the saints.
Prayer for the dead.
Monasticism, fasting and an ancient liturgical life.

The Catholic Church calls the Orthodox Churches true particular Churches, and Pope St Paul VI spoke of a communion between them “so profound that it lacks little to attain the fullness that would permit a common celebration of the Lord’s Eucharist” (CCC 838).

Where They Differ

1. The Pope

This is the central issue, from which most other differences flow.

Catholics believe that the Bishop of Rome, as successor of St Peter, has a primacy of authority over the whole Church, and that when he solemnly defines a doctrine of faith or morals, he is protected from error. (See Where Is the Papacy in the Bible?)

The Orthodox generally accept that Rome had a primacy of honour in the early Church, as first among the ancient patriarchates. But they reject the Pope’s universal jurisdiction and his infallibility as later developments. For them, the highest authority lies in ecumenical councils of all the bishops.

Pope St John Paul II, in his encyclical Ut Unum Sint (1995), invited other Christians to help him find a way of exercising the papal primacy that could be accepted by all. This dialogue continues.

2. The Filioque

Catholics in the Latin Church say in the Creed that the Holy Spirit proceeds “from the Father and the Son”; the Orthodox say “from the Father.” Theologians on both sides now often see this as a difference of emphasis rather than of faith, but it remains a point of discussion. (See What Is the Filioque?)

3. Purgatory

Both pray for the dead. But the Orthodox reject the Western term “purgatory” and its description in terms of punishment and satisfaction, preferring to speak more simply of an intermediate state in which the dead can be helped by prayer.

4. The Immaculate Conception

The Orthodox honour Mary as all-holy and free from personal sin. But they do not accept the 1854 dogma of the Immaculate Conception, partly because they understand original sin differently, and partly because it was defined by a pope alone. Most Orthodox, however, believe in Mary’s bodily assumption into heaven, which they celebrate as the Dormition.

5. Divorce and Remarriage

The Catholic Church holds that a valid sacramental marriage cannot be dissolved. The Orthodox Church also sees marriage as lifelong, but in certain circumstances, out of pastoral mercy (oikonomia), it permits a second or even third marriage after divorce, with a penitential rite.

6. Practices

Other differences are matters of custom, not doctrine:

Married priests: the Orthodox, like most Eastern Catholics, ordain married men; bishops are celibate.
Leavened bread in the Eucharist, rather than the Latin Church’s unleavened bread.
Infants receive Communion at baptism, along with chrismation (confirmation).
The calendar: many Orthodox Churches use the Julian calendar for some or all feasts, so Easter often falls on a different date.

Eastern Catholics

There is a bridge between the two: the Eastern Catholic Churches, which share the Orthodox liturgies and customs but are in full communion with the Pope. (See What Are the Eastern Catholic Churches?)

Not normally, because full communion does not yet exist. But Catholic law allows Orthodox Christians to receive Communion in a Catholic church if they ask on their own and are properly disposed, and permits Catholics to receive from Orthodox priests when they cannot reach a Catholic one (canon 844). The Orthodox Churches themselves generally do not permit this.

Towards Unity

In 1965, Pope Paul VI and Patriarch Athenagoras lifted the mutual excommunications of 1054. Since then, popes and patriarchs have met and prayed together many times, and a joint theological commission works on the remaining issues.

For Catholics, the Orthodox are not strangers but estranged brothers and sisters. St John Paul II often said that the Church must learn to breathe again with both her lungs, East and West. Many Catholics pray that this division, the oldest in Christianity, may one day be healed.