The Crusades were military campaigns sanctioned by the Roman Catholic Church during the High and Late Middle Ages.
The First Crusade (1095–1099) was a military expedition by Roman Catholic Europe to regain the Holy Lands taken in Muslim conquests, ultimately resulting in the recapture of Jerusalem.
The Second Crusade (1147–1149) was the second major crusade launched against Islam by Catholic Europe, started in response to the fall of the County of Edessa founded in the First Crusade; it was largely a failure for the Europeans.
The Third Crusade (1189–1192) was an attempt by European leaders to reconquer the Holy Land from the Muslim sultan Saladin; it resulted in the capture of the important cities Acre and Jaffa, but failed to capture Jerusalem, the main motivation of the crusade.
Crusading became increasingly widespread in terms of geography and objectives during the 13th century and beyond, and crusades were aimed more at maintaining political and religious control over Europe than reclaiming the Holy Land.