Crusades, on the religious side of things, were a vigorous campaign for political, social, or religious change. But, the other part of being a crusade was for the medieval military back in the 11th, 12th, and 13th centuries in Europe to recover the Holy Land from Muslims. They were mainly for religion because mainly of the Muslims because they were taking the Holy Land, and Europe did not want to give it up, so they protected the Holy Land, only to loose against the Muslims.
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