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

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Eastern Orthodoxy summary

Eastern Orthodoxy: Facts & Related Content

Written and fact-checked by The Information Architects of Encyclopaedia Britannica

Last Updated: Dec 23, 2025

News •

Gaza's tiny Christian community tries to capture the holiday spirit during the ceasefire • Dec. 23, 2025, 4:30 AM ET (AP)

Converts are finding Eastern Orthodoxy online. The church wants to help them commune face-to-face • Dec. 12, 2025, 7:14 AM ET (AP)

Pope Leo XIV doubles down on insistence for 2-state solution to resolve Israeli-Palestinian conflict • Nov. 30, 2025, 10:55 AM ET (AP)

Pope visits Istanbul's Blue Mosque without praying as he focuses on unifying Christians • Nov. 29, 2025, 6:49 PM ET (AP)

Pope joins patriarchs from East and West at historic Christian site in Turkey to pray for unity • Nov. 28, 2025, 11:32 AM ET (AP)

Facts

Also Known As	Orthodox Catholic Church • Orthodox Church

Photos and Videos

Jesus Christ: mosaic

St. Michael's Golden-Domed Monastery

Hagia Sophia mosaic

Peter the Hermit

Cathedral of St. Basil the Blessed

Explore Metéora Eastern Orthodox monasteries atop the Cambunian Mountains of Thessaly, Greece

Explore Eastern Orthodox monasteries run by isolated monks in the Balkans' mountainous interior

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Topics

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Key People

Pope Innocent IV

Innocent IV

pope

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Michael VIII Palaeologus

Byzantine emperor

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Eutyches

Orthodox abbot

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Isidore Of Kiev

Greek Orthodox patriarch

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Saint Theophilus of Alexandria

Egyptian theologian

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Demetrius Cydones

Byzantine scholar and statesman

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Theophylact of Ochrid

Greek archbishop

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Nicholas I

Byzantine patriarch of Constantinople

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John XI Becchus

patriarch of Constantinople

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Bessarion

Byzantine theologian

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Philotheus Kokkinos

patriarch of Constantinople

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Anthony III Studite

patriarch of Constantinople

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John VIII Palaeologus

Byzantine emperor

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Dioscorus

patriarch of Alexandria

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Athanasius I

patriarch of Constantinople

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Nicholas III

patriarch of Constantinople

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Arsenius Autorianus

patriarch of Constantinople

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Athenagoras I

Greek patriarch

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George Acropolites

Byzantine statesman and scholar

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Anthimus I

Byzantine patriarch

Holy week. Easter. Valladolid. Procession of Nazarenos carry a cross during the Semana Santa (Holy week before Easter) in Valladolid, Spain. Good Friday

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