The Crusades were horrible, bloody wars. There were seven of them, going from 1095 to 1250. They were caused by popes and king, followed by people, as military campaigns while trying to capture land. the first three were all about trying to capture Jerusalem but all ended up as failures. The ones that followed were all attempts to capture other lands. None of the Crusades were necessary as they accomplished nothing. The only problem was that the people who led the Crusades thought it was okay, because they were doing 'God's work'.