The Crusades were a series of wars fought to recapture and hold the Holy Lands that were captured by Muslim rulers. These were mainly fought between Catholic Europe and muslim kings. These crusades, nine total, took place between 1095-1272 and were a papal response to muslim conquests.
The first crusade was initiated on 27 November, 1095 by Pope Urban II to respond to a call by Alexios I Komnenos, the Byzantine Emperor, to support him against the invading Seljuq Turks from Anatolia. However, the campaign soon changed to reveal its real motive, one that lasted through the nine crusades: capture of the Holy Land of the City of Jerusalem and the freeing of the captured Christian cities in the East. The true nature of Crusades, whether offensive or defensive, is still open to debate.