crusade

The crusades were a series of religiously motivated military campaigns undertaken by Latin Christendom in the medieval period, primarily to recover or defend the Holy Land and other Christian territories. The term derives from the Latin crux, cross, and refers to participants who undertook a crusade, sometimes symbolically bearing the cross. The campaigns were officially endorsed by the papacy and framed as acts of piety, defense of fellow Christians, and protection of pilgrimage routes, with expectations of spiritual rewards.

Initiated in the late 11th century, the best known efforts spanned roughly 1096 to 1291. The First Crusade (1096–1099) succeeded in establishing several Crusader states, including the Kingdom of Jerusalem, County of Tripoli, Principality of Antioch, and County of Edessa. The Second Crusade (1147–1149) failed to achieve its main objectives, while the Third Crusade (1189–1192) sought to retake territory after Saladin's victories. The Fourth Crusade (1202–1204) culminated in the sack of Constantinople, diverting from the Holy Land. Later campaigns persisted in Iberia (Reconquista) and the Baltic regions (Northern Crusades).

Over time, the crusades produced lasting political outcomes, including the emergence and persistence of Crusader states, complex alliances, and ongoing military confrontations with Muslim powers. They also facilitated cultural and economic contacts, as refugees, merchants, and scholars moved between regions. The campaigns were marked by episodes of violence against combatants and noncombatants alike and are a source of enduring religious and political controversy. By the late 13th century, Christian control of major Levantine towns had collapsed, with Acre falling in 1291.

Scholars emphasize a multifaceted phenomenon, with religious fervor, dynastic politics, and economic motives alongside concerns for Christian communities and pilgrimage routes. In modern usage, the term is sometimes extended metaphorically to describe campaigns framed as moral or religious struggles, though such usage remains controversial.