Why did knights participate in crusades?

Knights participated in the Crusades primarily to reclaim the Holy Land, particularly Jerusalem, from Muslim control, which was seen as a sacred duty by the Catholic Church. They were motivated by religious fervor, the promise of spiritual rewards such as indulgences, and the opportunity for adventure and glory. Additionally, the Crusades offered knights a chance to gain wealth and land, as many sought to improve their social status and fulfill their feudal obligations.