The East-West Schism, known also as the Great Schism (though this latter term sometimes refers to the later Western Schism), was the event that divided Christianity into Western Catholicism and Greek Eastern Orthodoxy, following the dividing line of the Empire in Western Latin-speaking and Eastern Greek-speaking parts. Though normally dated to 1054, when Pope Leo IX and Patriarch of Constantinople Michael I Cerularius excommunicated each other, the East-West Schism was actually the result of an extended period of estrangement between the two Churches.