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 II bitter confrontations with Roger's Hohenstaufen heirs. Pope Urban was beatified in 1881 by Pope Leo XIII with his feast day on 29 July. Pope Urban II Pope Urban II (; – 29 July 1099), born Odo of Châtillon or Otho de Lagery, was Pope from 12 March 1088 to his death in 1099. Urban II was a native of France. He was a descendant of a noble family in Châtillon-sur-Marne. Reims was the nearby cathedral school that Urban, at that time Eudes, began his studies at 1050. Before his papacy he was the abbot of Cluny and Bishop of Ostia