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 Nicholas II Pope Nicholas II Pope Nicholas II (; c. 990/995 – 27 July 1061), born Gérard de Bourgogne, was pope from 24 January 1059 until his death. At the time of his election, he was Bishop of Florence. Gérard de Bourgogne was born in Chevron, in what is now Savoy. He was canon at Liege. In 1046 he became Bishop of Florence, where he restored the canonical life among the clergy of numerous churches. Benedict X was elected in 1058, his election having been arranged by the Count of Tusculum. However, a number of cardinals alleged that the election was irregular,