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 IV lands in northern Italy, nor in the Papal States. Charles promised to restore the annual "census" or feudal tribute due the Pope as overlord, some 10,000 ounces of gold being agreed upon, while the Pope would work to block Conradin from election as King of the Germans. Before the arrival in Italy of his candidate Charles, Urban IV died at Perugia on 2 October 1264. His successor was Pope Clement IV, who immediately took up the papal side of the arrangement. Tannhäuser, a prominent German Minnesänger and poet, was a contemporary of Pope Urban IV—the pope died in 1264, and