The Eastern and Western Christian Churches broke up in 1054 A.D. This breakup, an event historians call the Great Schism, eventually led to the development of the Roman Catholic Church in the West and the Eastern Orthodox Church in the East. In addition to the obvious differences in geography, there were several other important differences between the Greek-speaking Eastern and Latin-speaking Western Churches that led to the Great Schism.

Papal Jurisdiction

The Eastern and Western Churches disputed over their territories of jurisdiction. Pope Leo IX claimed authority over the four Eastern patriarchs. According to the Nigeria Parish of the Byzantine Catholic Church, Pope Leo IX undermined the authority of Eastern bishops because he believed he could change official church creeds without consulting the whole church.

Language Suppression

Eastern and Western Christianity had always been split upon linguistic lines, with the Eastern Christians speaking Greek and the Western Christians speaking Latin. But the language difference became an insurmountable problem by the time of the Great Schism when the head of the Catholic Church, Leo IX, suppressed Greek-speaking within his domain and the Patriarch of Constantinople, Michael Cerularius, suppressed Latin.

Church Structure and Theology

Roger E. Olson, in his book “The Story of Christian Theology: Twenty Centuries of Tradition & Reform,” said that the two halves of Christendom had developed their own distinctive ecclesiastical and theological traditions by the beginning of the 9th century. Over the centuries, the intellectual division grew more and more distinct, with the West insisting on the soveriengty of theological grace and the Eastern Church believing more in the concept of free will. According to Olson, the Eastern Orthodox Christians were the more mystical faction, placing a greater emphasis on worship than the Western Church.

Iconoclasm

While the Roman Catholic churches sometimes used icons as visual aids for their worship, Eastern Orthodox Christians gave the images far greater significance and veneration. Leo III the Isaurian (685-741) was a Byzantine Emperor who actually destroyed icons within the Eastern churches. Leo III made iconoclasm the official policy of the Empire in 730 A.D., when he outlawed the veneration of sacred images and he ordered the destruction of icons within churches. After this period of iconoclasm in the 8th century, the Western Church's iconoclasm became a major point of contention in the Eastern Church where icon veneration had been a practiced for centuries.