The Great Schism: How the Catholic Church Split up

The definitive break in 1054 did not emerge in isolation but was preceded by a long history of ecclesiastical conflicts and theological disputes. Among the central issues were the *Filioque* clause—an addition to the Nicene Creed by the Western Church asserting that the Holy Spirit proceeds from both the Father and the Son—the use of leavened versus unleavened bread in the Eucharist, the bishop of Rome’s assertion of universal jurisdiction, and the status of the See of Constantinople in relation to the pentarchy (the five major episcopal sees of the early Church). These disagreements highlighted fundamental differences in theological perspectives, liturgical practices, and ecclesiastical authority.

The formal steps toward the schism began in 1053 when Greek churches in southern Italy were ordered to conform to Latin traditions, under the threat of closure if they refused. In retaliation, Michael I Cerularius, the Patriarch of Constantinople, ordered the closure of all Latin churches in Constantinople. This act escalated tensions and set the stage for the events of 1054.