1054

The Great Schism of 1054

Patriarch Michael Cerularius of Constantinople was a firm opponent of Latin practice. In 1053 he closed the Latin churches and monasteries in the city. He circulated documents accusing the West of doctrinal and ritual errors. These included using unleavened bread, Saturday fasting, forbidding "Alleluia" in Lent, the Filioque, and clerical celibacy.

Pope Leo IX sent Cardinal Humbert as legate. Humbert knew no Greek and saw married clergy and imperial power over the church as enemies of reform. An exchange of insults followed. On 16 July 1054 the legate laid a bull of excommunication against Cerularius on the altar of Hagia Sophia. It was now issued in the name of the already-dead Pope Leo IX.

Cerularius responded by convening a council that condemned the West. Earlier breaks had been temporary, but this schism between Eastern Orthodoxy and Roman Catholicism proved final.

Reconciliation attempts continued into the 14th–15th centuries, at the Second Council of Lyon (1274) and the Council of Ferrara-Florence (1439). But they failed.