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
Roman Catholic Diocese of Saint-Flour of it except the church. Amblard and Astorg, from 1010 to 1013, gave this church and its fief to St. Peter's at Rome, together with the monastery of Sauxillanges, governed by Odilo; but later Amblard considered this donation as void, and constructed a fortress, a remnant of which is now the sacristy of the cathedral, on the site of the old monastery; afterwards Amblard, seized with remorse at Rome, between 1025 and 1031 gave back to Odilo all he possessed, and a large monastery was again founded. Pope Urban II, after the Council of Clermont (1095), consecrated the church of