Overview
The year 1054 is generally considered the date of the schism (split) between the Eastern and Western Christian churches. That year, delegates of Pope Leo IX issued an anathema (solemn curse of excommunication) against the patriarch of Constantinople. The patriarch then summoned a council that excommunicated the papal delegates. These mutual anathemas remained in force until 1965, when Patriarch Athenagoras I and Pope Paul VI lifted them.
Today, Eastern Orthodox Churches are the major Christian churches in Greece, Russia, eastern Europe, and western Asia. As a federation of churches, they are united by common beliefs and traditions. Individually, they are usually called by their national names, such as the Greek Orthodox Church or the Russian Orthodox Church. About 170 million people belong to the Eastern Orthodox Churches.
Excerpt adapted from the "Eastern Orthodox Churches" and the "Roman Catholic Church" articles, The World Book Encyclopedia © 1999