World Religions › Medieval › Great Schism between East and West
Eastern Orthodox Church
Separate from Rome after 1054; Byzantine roots· Religion or tradition· Judaism, Christianity & Islam
Historical recordConfirmed by archaeology, outside sources or contemporary records.
The family of self-governing churches of the Greek East and Slavic world, with about 260 million members by Pew's estimate.
See it on the World Religions map →What it is
Orthodox Christians see their church as the original church of the apostles, its faith unchanged. It is a communion of independent churches, such as the Greek, Russian, Serbian, Romanian and Georgian, each led by its own patriarch or archbishop; the patriarch of Constantinople is 'first among equals', not a pope. Worship centers on the ancient Divine Liturgy, icons and the teaching of seven ecumenical councils. Priests may marry before ordination; bishops are chosen from monks.
Why it matters
One of Christianity's three main branches, about 12% of Christians, it shaped the culture, alphabet and politics of Russia, Ukraine, Greece and the Balkans.
Sources and history
Continuous church records and councils since Byzantine times, surviving churches and icons, and Pew Research's 2017 survey, which found about 40% of Orthodox Christians live in Russia.
Questions and debates
Orthodoxy is divided over Ukraine: Moscow broke communion with Constantinople in 2018 after it moved to recognize an independent Ukrainian church, a dispute still unresolved.
Inside this (1)
Connections (5)
▸Constantine, the first Christian emperor founded Constantinople, later seat of Eastern Orthodox ChurchHistorical record
The connection
Constantine refounded the Greek town of Byzantium as Constantinople, his new Christian capital, in 330. Its bishop was ranked second only to Rome's in 381 and became the leading patriarch of the East. Orthodox Christians honor Constantine as a saint 'equal to the apostles', and the city remains the seat of their first-ranking patriarch.
When and where
Byzantium, on the Bosporus, dedicated May 11, 330; the patriarch of Constantinople still lives there, in Istanbul's Fener district.
Historical evidence
Roman histories, the canons of the councils of Constantinople (381) and Chalcedon (451) on the see's rank, and the patriarchate's continuous presence in Istanbul.
Questions and debates
How sincere and complete Constantine's own conversion was is debated; he was baptized only on his deathbed in 337, by a bishop later seen as heretical.
▸Council of Nicaea and the Nicene Creed shaped the creeds of Eastern Orthodox ChurchHistorical record
The connection
The Council of Nicaea (325) defined the Son as 'of one substance' with the Father, and its creed, expanded at Constantinople in 381, is recited at every Orthodox Divine Liturgy. The Orthodox treat Nicaea as the first of seven ecumenical councils that define true faith, and reject the West's later addition of filioque to the creed.
When and where
Nicaea (modern İznik, Turkey), 325, called by Constantine; about 250–318 bishops attended, mostly from the Greek-speaking East.
Historical evidence
The creed's text, the council's canons, and accounts by Eusebius and Athanasius, who attended; Orthodox service books still use the creed.
Questions and debates
Scholars debate whether the expanded creed really came from the 381 council, since it is first recorded only in 451; the filioque dispute remains unresolved.
▸Hagia Sophia was the great church of Eastern Orthodox ChurchHistorical record
The connection
For over 900 years Hagia Sophia was the cathedral of the patriarch of Constantinople and the stage for imperial coronations and the grandest Orthodox liturgy. A Russian chronicle says envoys of Prince Vladimir of Kyiv, attending a service there around 987, 'knew not whether we were in heaven or on earth', helping persuade him to adopt Orthodoxy.
When and where
Constantinople, from its dedication in 537 to the Ottoman conquest of May 29, 1453, except for Latin Catholic control after the crusader sack, 1204–1261.
Historical evidence
Byzantine liturgical and court records; the Russian Primary Chronicle (c. 1113); Christian mosaics of Christ, Mary and emperors still visible inside.
Questions and debates
The envoy story may be a later legend. Since 2020, how the Christian mosaics are covered during Muslim prayer has become a point of contention.
▸Great Schism between East and West created the separate Eastern Orthodox ChurchHistorical record
The connection
The 1054 excommunications and the 1204 sack of Constantinople left the Eastern churches, led by their patriarchs, lastingly out of communion with Rome. From then on Orthodoxy developed as its own body, rejecting papal supremacy and filioque, and keeping its own liturgy, calendar and married parish clergy.
When and where
Constantinople and Rome, 1054; hardened in 1204; attempts at reunion at Lyon (1274) and Florence (1439) failed.
Historical evidence
Council records of Lyon and Florence, whose reunion decrees Orthodox clergy and people rejected; the 1965 joint declaration lifting the excommunications.
Questions and debates
The Orthodox see Rome as having left the original church, Catholics see the reverse; dialogue continues, but full communion has not been restored.
▸Soviet state atheism persecuted Eastern Orthodox ChurchHistorical record
The connection
The Russian Orthodox Church, the old state church, was the main target. Its property was seized in 1918, Patriarch Tikhon was arrested in 1922, and great churches were demolished, like Moscow's Cathedral of Christ the Saviour in 1931. By 1939 only a few hundred of tens of thousands of prewar churches still functioned, by most estimates.
When and where
Across the USSR, with peaks in 1922, 1929–1939 and 1959–1964; Lenin, Stalin and Khrushchev; Stalin allowed a controlled revival from 1943.
Historical evidence
Soviet archives opened after 1991, Church lists of 'new martyrs', and the rebuilt Cathedral of Christ the Saviour, completed in 2000.
Questions and debates
Clergy death tolls are uncertain, and the Church's past cooperation with the KGB and its close ties to today's Kremlin remain contested.