Eastern Orthodoxy

Introduction
Nature and significance
- The cultural context
- The norm of church organization
History
- The church of imperial Byzantium
  - Byzantine Christianity about 1000 ce
    - Relations between church and state
    - Monastic and mission movements
    - Relations with the West
  - Invasions from east and west
    - The Crusades
    - The Mongol invasion
  - Attempts at ecclesiastical union and theological renaissance
    - Relations with the Western church
    - Theological and monastic renaissance
- Orthodoxy under the Ottomans (1453–1821)
  - The Christian ghetto
  - Relations with the West
- The church of Russia (1448–1800)
  - The “third Rome”
    - Origin of the Muscovite patriarchate
    - Relations between patriarch and tsar
  - The reforms of Peter the Great (reigned 1682–1725)
- Orthodox churches in the 19th century
  - Autocephalies in the Balkans
    - In Greece
    - In Serbia
    - In Romania
    - In Bulgaria
  - The church in imperial Russia
- The Eastern Orthodox Church since World War I
  - The Russian Revolution and the Soviet period
  - The Balkans and eastern Europe
  - The Eastern Orthodox Church in the Middle East
  - Orthodoxy in the United States
  - The Orthodox diaspora and missions
  - Ecumenical involvement
Doctrine
- Councils and confessions
- God and humankind
- Christ
- The Holy Spirit
- The Holy Trinity
- The transcendence of God
- Modern theological developments
The structure of the church
- The canons
- The episcopate
- Clergy and laity
- Monasticism
Worship and sacraments
- The role of the liturgy
- The eucharistic liturgies
- The liturgical cycles
- The sacraments
  - Baptism and chrismation
  - The Eucharist
  - Orders
  - Penance
  - Anointing of the sick
  - Marriage
- Architecture and iconography
The church and the world
- Missions: ancient and modern
- Orthodoxy and other Christians
- Church, state, and society

References & Edit History Quick Facts & Related Topics

Images & Videos

Jesus Christ: mosaic

St. Michael's Golden-Domed Monastery

Hagia Sophia mosaic

Peter the Hermit

Cathedral of St. Basil the Blessed

Patriarch Bartholomew I of the Eastern Orthodox Church, wearing ornate religious vestments and a jeweled mitre, holds a staff and censer during an outdoor service.

At a Glance

mosaic

Eastern Orthodoxy summary

Related Questions

Jesus Christ: mosaic — Jesus Christ: mosaic Jesus Christ, detail of the Deesis mosaic, from the Hagia Sophia in Istanbul, 12th century.

Eastern Orthodoxy

Christianity

Also known as: Orthodox Catholic Church, Orthodox Church

Written by

John Meyendorff

Fact-checked by

Britannica Editors

Last updated

Nov. 12, 2026 •History

Eastern Orthodoxy, one of the three major doctrinal and jurisdictional groups of Christianity. It is characterized by its continuity with the apostolic church, its liturgy, and its territorial churches. Its adherents live mainly in the Balkans, the Middle East, and former Soviet countries. Eastern Orthodoxy is the large body of Christians who follow the faith and practices that were defined by the first seven ecumenical councils. The word orthodox (“right believing”) has traditionally been used...

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