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 Avignon. He was appointed by the Bishop of Clermont, Pierre de Aigrefeuille (1349-1357) to be his Vicar General, which meant in effect that he ruled the diocese on behalf of the bishop. When Bishop Pierre was transferred to Uzès (1357-1366), Guillaume Grimond became Vicar General of Uzès. Guillaume was named abbot of the monastery of Saint-Germain en Auxerre on 13 February 1352 by Pope Clement VI. In 1359 the town and abbey were captured by the English and subjected to heavy imposts. In the summer of 1352 Pope Clement VI summoned Abbot Guillaume for an assignment. Northern Italy had been