What is a “crusade”?

The story behind the answer

Called by Pope Urban II in 1095, these were papally sanctioned armed expeditions undertaken by Latin Christians to conquer and defend Jerusalem and other sacred sites in the eastern Mediterranean. Participants took a vow, sewed crosses on their garments, and were promised spiritual benefits such as indulgences, framing warfare as a form of penitence and service to God.

Over two centuries, multiple campaigns unfolded, creating military orders like the Templars and Hospitallers, reshaping Mediterranean trade, and intensifying cross-cultural contact—and conflict. While often confused with a pilgrimage (a nonviolent journey) or church reform movements, these campaigns were organized warfare with religious goals and leadership, sparked in part by appeals from the Byzantine Empire and sustained by devotion, prestige, and politics.