The primary motivation behind the Crusades, a series of religious wars initiated in the late 11th century, was the desire to reclaim Jerusalem and other holy sites in the Middle East from Muslim control. Christian Europeans were driven by religious fervor, aiming to secure their pilgrimage routes and restore Christian control over sacred locations. Additionally, the Crusades were influenced by political and economic factors, including the expansion of European power and the desire for new trade routes. This complex interplay of religion, culture, and ambition significantly shaped medieval history and Christian-Muslim relations.