Pope military aid from Pope Urban II in the ongoing Byzantine–Seljuq wars. Urban, at the council of Clermont, called the First Crusade to assist the Byzantine Empire to regain the old Christian territories, especially Jerusalem. With the East–West Schism, the Eastern Orthodox Church and the Catholic Church split definitively in 1054. This fracture was caused more by political events than by slight divergences of creed. Popes had galled the Byzantine emperors by siding with the king of the Franks, crowning a rival Roman emperor, appropriating the Exarchate of Ravenna, and driving into Greek Italy. In the Middle Ages, popes struggled with
Pope Urban V Legate to Italy to arrange the business. Then, through the mediation of Holy Roman Emperor Charles IV, Urban lifted his excommunication against Bernabò, obtaining Bologna only after he signed a hasty peace that was highly favorable to Bernabò. In May 1365 the Emperor Charles visited Avignon, where he appeared with the Pope in full imperial regalia. He then proceeded to Arles, which was one of his domains, where he was crowned King by the Archbishop, Pierre de Cros, OSB. Urban V's greatest desire was that of a crusade against the Turks. In 1363, King John II of France and Peter