Church Schism of 1054

   This was the last of several church schisms that began with the Akkakian Schism (q.v.) of 484-519. This schism, despite its circumstantial appearance, can be seen as a culmination of a gulf between the churches that developed since the ninth century. The immediate events are the following. Humbert (q.v.), secretary and ambassador from Pope Leo IX (qq.v.) left an intemperate bull of excommunication on the altar of Hagia Sophia (q.v.) The bull was drawn up by Humbert himself, without authorization of the pope (who, in any case, had just died, making Humbert's authority technically invalid). It contained what had become the usual litany of complaints about Byzantine church doctrine and liturgical practices, e.g., Byzantine use of leavened bread in the Eucharist (rather than azyma [q.v.]), and a creed that did not contain the filioque (q.v.). That the schism was not healed has much to do with the stubborn resistance of Patriarch Michael I Keroularios (qq.v.), who reciprocated the excommunication. For the first time the Byzantine church learned of the Donation of Constantine (q.v.) and how it supported the doctrine of papal primacy (q.v.). That these differences in doctrine and liturgical practices proved enduring can be attributed in part to the Crusades. In particular the Fourth Crusade's (qq.v.) conquest of Byzantium (q.v.), which resulted in the forcible submission of Byzantine clergy to the papacy (q.v.) from 1204-1261, aroused widespread hostility against the western church. Further attempts to achieve a union of the churches (q.v.) at the Council of Lyons and at the Council of Ferrara-Florence (qq.v.) were on paper only, done to gain military aid from the West. Thus, Humbert's rash action mushroomed into something far more significant and enduring.