Definition
The Great Schism refers to the enduring division of Christianity into the Roman Catholic Church, centered on Rome and the Latin West, and the Eastern Orthodox Church, centered on Constantinople and the Greek East. The split is conventionally dated to the eleventh century.
The term is sometimes also used for a later division within the Western church, but in world history it most commonly names this East-West rupture, which has never been healed.
Why it matters
How it works
The schism was not a single event but the culmination of long-building differences. Theological disputes — most notably the filioque clause — combined with disagreements over the authority of the pope, differences in language and ritual, and political rivalry between Rome and Constantinople. Tensions hardened until church leaders excommunicated one another, formalizing the break. Afterward, the two churches developed separately in doctrine, liturgy, and governance. The Great Schism remains a defining feature of the religious map of Europe.