Historically, the Crusades were a series of several military campaigns, usually sanctioned by the Papacy, that took place during the 11th through 13th centuries. Originally, they were Roman Catholic endeavors to capture the Holy Land from the Muslims. Some were directed against other Christians, such as the Fourth Crusade against Constantinople and the Albigensian Crusade against the Cathars of southern France. (In a broader sense, "crusade" can be used to refer to any war waged for religious reasons.)