Pope Urban II (Latin: Urbanus II; c.1035 29 July 1099), otherwise known as Odo of Chtillon 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 served as the catalyst for the Crusades.Pope Urban was a native of France, and was a descendant of a noble family from the French commune of Chtillon-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 (109699). 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.

The Council of Clermont was a mixed synod of ecclesiastics and laymen of the Catholic Church, called by Pope Urban II and held from 17 to 27 November 1095 at Clermont, Auvergne, at the time part of the Duchy of Aquitaine.Pope Urban's speech on 27 November included the call to arms that would result in the First Crusade, and eventually the capture of Jerusalem and the establishment of the Kingdom of Jerusalem. In this, Urban reacted to the request by Byzantine emperor Alexius I Comnenus who had sent envoys to the Council of Piacenza requesting military assistance against the Seljuk Turks.

Several accounts of the speech survive; of these, the one by Fulcher of Chartres, who was present at the council, is generally accepted as the most reliable.

Urban also discussed Cluniac reforms of the Church, and also extended the excommunication of Philip I of France for his adulterous remarriage to Bertrade of Montfort. The council also declared a renewal of the Truce of God, an attempt on the part of the church to reduce feuding among Frankish nobles.