What is one reason behind pope urban ii's decision to launch the first crusade

Pope Urban II was Pope No. 159 of the Catholic Church, between 1088 and 1099, in opposition to the antipope Clement III (1080-1100). He succeeded the reformer Gregory VII in full complaint of the Investiture between the Papacy and Empire, a conflict that overlapped with the regeneration of the Church, because of the then widespread practice of simony, Nicolais and nepotism.

He is known for his preaching of the First Crusade (1094-1099) for the recovery of the Holy Land, by then under Muslim rule, although he died before the culmination of it with the capture of Jerusalem. He also reformed the papal administration and established the Roman Curia in its current form. He is venerated as blessed in the Catholic Church.

would not cooperate with each other voluntarily.