Schism (religion)
Any Christian communion or sect that has left the One Holy Catholic and Apostolic Church. Which church constitutes the One Holy Catholic and Apostolic Church has long been disputed: for instance, the  Roman Catholic Church claims that title and thinks the Eastern Orthodox Communion to be in schism. The Eastern Orthodox Communion also claims that title and holds that the Catholic Communion is schismatic. The Protestant movement thinks that both are in error, so does the Restorationist movement.