article: East–West Schism
links: Eastern Roman Empire Excommunication Schism Schism (religion) 8th century Byzantine Empire Reconciliation Balkans Franks Byzantine Eastern Orthodox Latin language Nicene Creed First Council of Nicaea Roman Catholic Church Constantinople Language Patriarchate of Constantinople Holy Spirit in Christianity Oriental Orthodoxy Apostolic vicariate Eastern Orthodox Church Pope Leo IX Christianity Filioque Nicene creed Nestorianism 1054 Middle Ages Pope Nicholas I Western Roman Empire 5th century Christian denomination Ancient Greek language Doctrine Eastern Orthodoxy Roman Catholicism 6th century Hagia Sophia Cardinal (Catholic Church) Bishop