Why did the crusades in the east begin?

Officially, Pope Urban II called for the Crusade. The goal of the campaign was the liberation of the Holy Land and the Holy Sepulcher from the infidels (Saracens). Along with this, many issues for the countries of Western Europe were also resolved. For example, the leaders of the army sought to establish their principalities and kingdoms in the east. The impoverished knights wanted to seize loot and land, ordinary soldiers went east in search of a better life, since their situation in Europe was the most difficult. The priests promised the participants in the campaign forgiveness of all sins and a place in paradise.