The Crusades began in 1095 and raged, on and off, for the next two hundred years. During these centuries, the western Christian world pitted itself against what it thought of as the infidel, or the unbelievers, in the Middle East. In particular, Crusaders, (those who had "taken the cross," as this fighting for Christianity was called at the time), were battling for reoccupation of the shrines and sites holy to Christians in...