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 VI the reconstruction of Saint Peter's Basilica, Urban's remains were almost dumped out to be destroyed so his sarcophagus could be used to water horses. The sarcophagus was saved only when church historian Giacomo Grimaldi arrived and, realizing its importance, ordered it preserved. Pope Urban VI's successor was Pope Boniface IX. Pope Urban VI Pope Urban VI (; c. 1318 – 15 October 1389), born Bartolomeo Prignano (), was Pope from 8 April 1378 to his death in 1389. He is so far the last pope to be elected from outside the College of Cardinals. His reign, which began shortly after