The Great Schism of 1054

The Eastern Christian Church (whose seat was located in Constantinople) and the Western Christian Church (located at Rome) were in communion from the earliest times of their history until a separation in 1054 CE. The reasons for the schism are complex and was not the result of a single episode or event. There had always been quarreling between the two communions over a variety of heresies and theological points. However, the claim of the primacy of the Bishop of Rome, which later resulted in the proclaiming of his infallibility, is considered the main cause of separation of the Western branch of the Christian Church from the Eastern.

General definition of Schism (a highly technical and lengthy article from the Catholic Encyclopedia.

A description of the Great Schism from a Roman Catholic perspective (from the Catholic Encyclopedia).

A description of the Great Schism from the Orthodox (Eastern) perspective (lengthy but readable). By: Rev. George Mastrantonis, Greek Orthodox Archdiocese of America.

A simple and direct definition of the Great Schism (from BELIEVE Religious Information Source, a “collection of around 1,500 articles by respected scholars on around 700 religious subjects.”