Why did pope urban ii call for a council of clermont in 1095?

Pope Urban II called for the Council of Clermont in 1095 primarily to address the growing threat of Muslim expansion into Byzantine territory and to respond to a plea for military assistance from Byzantine Emperor AlexiOS I Komnenos. The council aimed to unite Christians in a crusade to reclaim the Holy Land, particularly Jerusalem, from Muslim control. Urban sought to mobilize support from Western Europe, promising spiritual rewards and forgiveness of sins for those who participated in the crusade. This call ultimately marked the beginning of the First Crusade.