The Great Schism of 1054

The event

Tensions between the Latin-speaking Western church, centered on Rome, and the Greek-speaking Eastern church, centered on Constantinople, had accumulated for centuries over a range of theological, liturgical, and political disputes: the Filioque controversy over whether the Nicene Creed should describe the Holy Spirit as proceeding "from the Father and the Son" (a Western addition the East rejected as an unauthorized alteration of the original creed); differing practices around clerical celibacy, unleavened versus leavened Eucharistic bread, and fasting customs; and, underlying much of the friction, competing claims about the nature and extent of papal authority over the wider church.

Matters came to a head in 1054 when Pope Leo IX sent legates, led by Cardinal Humbert of Silva Candida, to Constantinople to negotiate a dispute partly connected to Norman military pressure in southern Italy and disagreements with the Patriarch of Constantinople, Michael Cerularius. Negotiations broke down acrimoniously, and on July 16, 1054, Humbert placed a bull of excommunication against Cerularius on the altar of the Hagia Sophia; Cerularius responded days later by excommunicating Humbert and his fellow legates in turn.

At the time, the exchange of excommunications was a relatively narrow act targeting specific individuals rather than a formal declaration that the entire Eastern and Western churches were mutually anathematized, and contemporaries on both sides did not necessarily view 1054 itself as a definitive, permanent rupture — earlier and later periods saw similar temporary breaks and reconciliations, including the earlier ninth-century Photian Schism.

However, the mutual bitterness of 1054, compounded by later events — most damagingly the sack of Constantinople by Western Crusaders during the Fourth Crusade in 1204 — hardened into a lasting institutional division between what became the Roman Catholic Church and the Eastern Orthodox Church, a split that despite modern ecumenical efforts, including the mutual lifting of the 1054 excommunications by Pope Paul VI and Patriarch Athenagoras in 1965, remains unresolved to the present day.

Other witnesses

• Cardinal Humbert's bull of excommunication (1054, surviving text)
• Michael Cerularius's response excommunicating the legates

Further reading

• Christian History Magazine 54: Eastern Orthodoxy, Then and Now — free full issue
• Catholic Encyclopedia (1913): The Eastern Schism — a Western Catholic account, written in 1912