The Crusades were a series of military expeditions to reclaim the Holy Land.
Most commonly, the term refers to campaigns launched by Latin Christian powers from the late 11th century onward, especially those aimed at Jerusalem and other sacred sites in the eastern Mediterranean. Pope Urban II’s call at the Council of Clermont in 1095 helped spark the First Crusade, which captured Jerusalem in 1099.
The Crusades were not one continuous war. There were several major expeditions, including the Second, Third, and Fourth Crusades, along with later campaigns. Their participants included nobles, knights, rulers, clergy, and ordinary pilgrims, and their motives ranged from religious devotion to political ambition, wealth, and territorial power.
A common mix-up is treating the Crusades as a synonym for the Reconquista or the Inquisition. Those were different historical movements, although medieval writers sometimes used crusading language for campaigns outside the Holy Land. The Fourth Crusade even attacked Constantinople in 1204 instead of reaching Jerusalem.