Pope Urban II (; – 29 July 1099), otherwise known as Odo of Châtillon or Otho de Lagery, was the head of the Catholic Church and ruler of the Papal States from 12 March 1088 to his death. He is best known for convening the Council of Clermont which ignited the series of Christian conquests known as the Crusades. Pope Urban was a native of France, and was a descendant of a noble family from the French commune of Châtillon-sur-Marne. Reims was the nearby cathedral school where he began his studies in 1050. Before his papacy, Urban was the grand prior of Cluny and bishop of Ostia. As pope, he dealt with Antipope Clement III, infighting of various Christian nations, and the Muslim incursions into Europe. In 1095 he started preaching the First Crusade (1096–99). He promised forgiveness and pardon for all of the past sins of those who would fight to reclaim the holy land from Muslims and free the eastern churches. This pardon would also apply to those that would fight the Muslims in Spain. While the First Crusade resulted in occupation of Jerusalem from the Fatimids and consequent massacre of the muslim population there, Pope Urban II died before he could receive this news. He also set up the modern-day Roman Curia in the manner of a royal ecclesiastical court to help run the Church. He was beatified by Pope Leo XIII on 14 July 1881. Bishop of Ostia Urban, baptized Eudes (Odo), was born to a family of Châtillon-sur-Marne. He was prior of the abbey of Cluny, later Pope Gregory VII named him cardinal-bishop of Ostia . He was one of the most prominent and active supporters of the Gregorian reforms, especially as legate in the Holy Roman Empire in 1084. He was among the three whom Gregory VII nominated as papabile (possible successors). Desiderius, the abbot of Monte Cassino, was chosen to follow Gregory in 1085 but, after his short reign as Victor III, Odo was elected by acclamation at a small meeting of cardinals and other prelates held in Terracina in March 1088. Papacy Struggle for authority From the outset, Urban had to reckon with the presence of Guibert, the former bishop of Ravenna who held Rome as the antipope "Clement III". Gregory had repeatedly clashed with the emperor Henry IV over papal authority. Despite the Walk to Canossa, Gregory had backed the rebel