During the 11th century, the East–West schism permanently divided Christianity.[87] It arose over a dispute on whether Constantinople or Rome held jurisdiction over the church in Sicily and led to mutual excommunications in 1054.[87] The Western (Latin) branch of Christianity has since become known as the Catholic Church, while the Eastern (Greek) branch became known as the Orthodox Church.[88][89] The Second Council of Lyon (1274) and the Council of Florence (1439) both failed to heal the schism.[90] Some Eastern churches have since reunited with the Catholic Church, and others claim never to have been out of communion with the pope.[89][91] Officially, the two churches remain in schism, although excommunications were mutually lifted in 1965.[92]