What was the Great Schism?
The Great Schism of 1054 was the formal split between Roman Catholic Christianity in the West and Eastern Orthodox Christianity in the East. Caused by theological disputes (particularly the filioque controversy), competing claims of papal authority, and centuries of cultural divergence, the schism permanently divided Christendom along lines that persist today.
The Great Schism of 1054 was the formal break between the Roman Catholic Church, centered in Rome, and the Eastern Orthodox Church, centered in Constantinople. While the dramatic mutual excommunications of 1054 are the conventional date, the schism was really the culmination of centuries of growing theological, linguistic, cultural, and political divergence between the western and eastern halves of Christendom.
The theological flashpoint was the filioque controversy. The original Nicene Creed stated that the Holy Spirit 'proceeds from the Father.' Western theologians added the phrase 'and from the Son' (filioque in Latin) without consulting the Eastern churches — a unilateral alteration to shared doctrine that the East considered both theologically wrong and procedurally illegitimate.
But the deeper issue was authority. The Bishop of Rome (the Pope) claimed supreme jurisdiction over all Christians — a claim the Eastern patriarchs never accepted. They insisted on a collegiate model in which the five major patriarchs (Rome, Constantinople, Alexandria, Antioch, Jerusalem) shared authority, with Rome holding a position of honor but not command. Cultural differences reinforced the divide: the West used Latin, the East used Greek; liturgical practices, clerical celibacy rules, and theological emphases all diverged.
The formal break came in July 1054 when papal legates placed a bull of excommunication on the altar of the Hagia Sophia in Constantinople. Patriarch Michael Cerularius excommunicated them in return. Though not seen as permanent at the time, subsequent events — particularly the catastrophic Fourth Crusade's sack of Constantinople in 1204 — made reconciliation impossible. The schism shaped the cultural identity of entire civilizations: Western Europe became Catholic, while Eastern Europe, Russia, and the Balkans became Orthodox.