Crusades were military expeditions against various enemies of the church; the term refers particularly to the medieval campaigns aimed at liberating the Holy Land from the Muslims. The word crusade (Span., cruzada; Fr., croisade) derives from the Latin crux (cross); the Latin term cruciata does not occur before the thirteenth century. It recalls the ceremony of "taking the cross" (Mt. 10:38), the public act of committing oneself to participate in a crusade. Crusaders wore a red cloth cross sewn to their cloaks as a sign of their status. In modern times the word crusade is used metaphorically to designate evangelistic efforts at promoting all kinds of religious or moral causes.

Roots and Causes

While the roots of the movement were complex, a major religious impulse came with the fusion of pilgrimage and holy war. The Crusades continued the old tradition of pilgrimage to the Holy Land that...