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 Crusades, and establishing the objectives, his letters to the Catalonian lords instead beseech them to continue the fight against the Moors, assuring them that doing so would offer the same divine rewards as a conflict against the Seljuks. It is Urban II's own letters, rather than the paraphrased versions of his speech at Clermont, that reveal his actual thinking about crusading. Nevertheless, the versions of the speech have had a great influence on popular conceptions and misconceptions about the Crusades, so it is worth comparing the five composed speeches to Urban's actual words. Fulcher of Chartres has Urban saying this: