Bible & Christianity › The medieval church
Great Schism: East and West split
July 16, 1054· Event· Bible story & events
Historical recordConfirmed by archaeology, outside sources or contemporary records.
In 1054 papal envoys and the Patriarch of Constantinople excommunicated each other, the symbolic break between the Catholic West and Orthodox East.
See it on the Bible & Christianity map →What it is
The Latin West and Greek East had drifted apart for centuries over language, the pope's authority, and the 'filioque', a Latin addition to the Nicene Creed. On July 16, 1054, Cardinal Humbert, sent by Pope Leo IX, laid a bull of excommunication on the altar of Hagia Sophia against Patriarch Michael Cerularius, who excommunicated the envoys in return. Lesser quarrels included leavened versus unleavened communion bread. The crusaders' sack of Constantinople in 1204 made the split bitter and lasting.
Why it matters
It divided Christianity into the Catholic and Eastern Orthodox churches, still separate today. In 1965 Pope Paul VI and Patriarch Athenagoras lifted the 1054 excommunications, but full communion has not returned.
Think of it like
Like a partnership dissolving: the formal notice has a date, but the split had been building for years over who controls decisions.
Sources and history
Humbert's bull and Cerularius's reply survive, with letters from both sides. Historians stress 1054 was not seen as final then; reunions were attempted at Lyon (1274) and Florence (1439) and failed.
Questions and debates
When the real break happened (1054, 1204, or gradually) is debated. Leo IX had died three months before the bull was laid, so its legal validity is questioned.
Inside this (1)
Connections (5)
▸The Nicene Creed gained a Western 'filioque' that helped cause Great Schism: East and West splitHistorical record
The connection
The creed of 381 says the Holy Spirit 'proceeds from the Father'. Western churches added 'and the Son' (filioque), first in Spain in 589; Rome adopted it around 1014. The East saw a one-sided change to a shared creed and a theological error, and it figured in the 1054 excommunications.
When and where
Third Council of Toledo, Spain, 589; condemned by Patriarch Photius of Constantinople in 867; sung at papal Mass in Rome from about 1014.
Historical evidence
The texts are clear: the Greek creed lacks the word, the Latin has it. Humbert's 1054 bull even accused the Greeks of deleting it.
Questions and debates
How much the filioque mattered compared with papal power is debated. Some theologians now see the dispute as partly verbal; Catholics omit it when reciting the creed in Greek.
▸Constantinople, the 'New Rome' led the East in Great Schism: East and West splitHistorical record
The connection
As the 'New Rome', Constantinople saw its patriarch as second only to Rome in honor, and resented papal claims to rule the whole church. Patriarch Michael Cerularius closed the city's Latin-rite churches around 1053, and his clash with papal envoys in 1054 ended in mutual excommunication.
When and where
Hagia Sophia, Constantinople, July 16, 1054: Patriarch Michael Cerularius against Cardinal Humbert of Silva Candida, legate of Pope Leo IX.
Historical evidence
Documented in the surviving bull, Cerularius's synod decree of July 1054, and letters between the parties.
Questions and debates
Whether Cerularius sought the break or the hot-tempered Humbert provoked it is debated; Emperor Constantine IX wanted an alliance with Rome against the Normans.
▸The papacy: the popes and medieval Christendom pressed claims that helped cause Great Schism: East and West splitHistorical record
The connection
From the 1050s reforming popes claimed authority over the whole church, East included. The East granted Rome first place in honor but not the right to rule. Leo IX's envoys demanded Constantinople accept Roman supremacy, and the dispute ended in mutual excommunication.
When and where
Rome and Constantinople, 1053–1054: Pope Leo IX, Cardinal Humbert and Patriarch Michael Cerularius.
Historical evidence
Letters sent in Leo IX's name asserting Roman primacy survive, as do Eastern replies rejecting it.
Questions and debates
How the early church understood the bishop of Rome's role is still debated by Catholic and Orthodox scholars in official dialogues, such as the Ravenna document of 2007.
▸Great Schism: East and West split separated Rome from Eastern Orthodox ChurchHistorical record
The connection
The 1054 excommunications mark the point when the Greek-speaking churches led by Constantinople and the Latin church under Rome became separate communions. The Eastern side came to be known as the Eastern Orthodox Church, the Western as the Roman Catholic Church.
When and where
Constantinople, July 1054; hardened by the 1204 sack; failed reunions at Lyon (1274) and Florence (1439).
Historical evidence
The outcome is clear, but historians stress it was gradual: in some places Eastern and Western Christians kept sharing communion long after 1054.
Questions and debates
Since 1965, when Pope Paul VI and Patriarch Athenagoras lifted the excommunications, theologians debate what still divides them; full communion has not been restored.
▸Ecumenism and the World Council of Churches began to heal Great Schism: East and West splitHistorical record
The connection
On December 7, 1965, Pope Paul VI and Patriarch Athenagoras I of Constantinople lifted the mutual excommunications of 1054, regretting the 'offensive words' on both sides. Their January 1964 meeting in Jerusalem was the first between a pope and that patriarch in over 500 years. Formal Catholic–Orthodox theological dialogue began in 1980.
When and where
Jerusalem, January 1964; the joint declaration read simultaneously in Rome and Istanbul, December 7, 1965. Later popes and Patriarch Bartholomew have continued the meetings.
Historical evidence
The 1965 Joint Catholic–Orthodox Declaration is published by both churches; photographs and records of the meetings survive.
Questions and debates
Lifting excommunications did not restore shared communion. Papal authority and the filioque remain unresolved, and the Orthodox are themselves divided: Moscow broke with Constantinople in 2018 over Ukraine.