Great Schism

1. The formal split between the Eastern Orthodox and the Roman Catholic churches in 1054 AD.

2. The interval from 1378 to 1417 AD when as many as three individuals simultaneously claimed to be pope. The Council of Constance (1414-18) eventually made Martin V the legitimate pope.

A schism is any formal and willful separation from the unity of the Christian church. The Great schism occurred in 1054 when the Eastern church formally split from the Western church.