Why did the church call for the crusade or holy wars?

The Muslims had control over Palestine, where Jesus lived and died (especially Jerusalem, which is located in Palestine). The Crusades were an attempt to put Christians back in control of Palestine. The Crusades were for the most part a failed military disaster, and finally the Christians and the Muslims came to an agreement: The Muslims would continue to control Palestine, and the Christians were allowed to visit there and make pilgrimages to Holy Sites in Palestine.