The East–West Schism is the medieval division of Chalcedonian Christianity into Eastern (Greek) and Western (Latin) branches, which later became commonly known as the Eastern Orthodox Church and the Roman Catholic Church, respectively. The East–West Schism is the larger and more lasting of the two schisms to which the term “Great Schism” is applied (the other being the Western Schism).
Relations between East and West had long been embittered by ecclesiastical differences and theological disputes. Prominent among these were the issues of the source of the Holy Spirit (“filioque”), whether leavened or unleavened bread should be used in the Eucharist,[a] the Pope’s claim to universal jurisdiction, and the place of Constantinople in relation to the Pentarchy.[8