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
Primate of the Gauls that the Church of Lyons had enjoyed this privilege "per annorum longa curriccula". His intent was to reduce the power of the Archbishop of Sens, but the pope also limits the powers of the tital itself, the holder is not a court of appeal, and he no longer holds the apostolic vicariate. The primacy of Lyon is challenged regularly, and at the Council of Clermont of 1 December 1095, Pope Urban II again confirms the privileges of Lyon and declares that the Archbishop of Sens had to be in submission and obedience to the primate. It was only in 1516