The Crusades were a series of religious wars initiated by European Christians from the late 11th to the late 13th centuries, primarily aimed at reclaiming Jerusalem and other holy sites in the Middle East from Muslim control. These military campaigns were marked by significant violence and conflict, as well as complex interactions between different cultures and religions. The Crusades had lasting impacts on Christian-Muslim relations, European politics, and trade. Ultimately, they failed to achieve their primary goal of permanently securing the Holy Land for Christianity.