What caused the east-west schism in the Catholic church?

The East-West Schism (split) of the Catholic Church was
caused by cultural, geographical, and political differences. The beginnings of the
schism dates back to as early as the division of the Roman Empire in A.D. 375 by Emperor
Theodosius. He divided the empire into the Eastern and Western Roman Empires and moved
the capital city from Rome to Constantinople (present-day Istanbul, Turkey). As a result
of this division, an informal split within the Catholic Church took place leading to the
formation of an Eastern Church in Constantinople and a Western Church in
Rome.

This informal split deepened in the 800s when a
series of disputes arose between the pope, the head of the Catholic Church, and the
patriarch of Constantinople (also called the ecumenical patriarch), head of the Catholic
Church in the East. The issue was the pope's authority over Christians in the East.
Finally, in 1054, Pope Leo IX (1002–1054) issued an anathema (a formal curse) against
the patriarch of Constantinople, Michael Cerularius (c. 1000–1059). The pope
excommunicated (expelled) the patriarch and his followers from the Catholic Church. As a
result, the Catholic Church was now officially split in two parts: the Roman Catholic
Church in the West and the Eastern (or Byzantine) Orthodox Church in the East.
Thereafter the Eastern Orthodox Church would accept the patriarch of Constantinople as
the highest authority and would no longer recognize the pope. Members of the Eastern
Orthodox Church followed the Byzantine rite (ceremonies); in the West, Roman Catholics
followed the Latin rite and continued to regard the pope as their
leader.

The capture of Constantinople in 1453 by the
Ottoman Empire placed the Eastern Orthodox Church under Muslim rule until the 1800s. By
the late twentieth century differences still remained between the Roman Catholic Church
and the Eastern Orthodox Church, which now included the Greek Orthodox Church and the
Russian Orthodox Church. However, the rift was somewhat healed in 1964 when Pope Paul VI
(1897–1978) met with Ecumenical Patriarch Athenagoras I (1886–1972) in Jerusalem. The
next year, each of the two religious leaders lifted the anathemas against the other's
church.

Further Information:
Bokenkotter, Thomas S. A Concise History of the Catholic Church.
Garden City, N.Y.: Doubleday, 1990; Deedy, John. Retrospect: The Origins of
Catholic Beliefs and Practices. Chicago: Thomas More Press, 1990; "Great
East-West Schism." Encyclopedia Britannica. [Online] Available
www.britannica.com/bcom/eb/article/5/0,5716,108295+16,00.html, October 20,
2000.