" While the First and Fourth Crusades could reasonably be described as successful, the majority of the other seven crusading expeditions to the Muslim east ended with disaster. Over two centuries, repeated attempts to reclaim the Holy Land of Jerusalem ended in failure and yet, again and again, ordinary people took the cross and made the arduous journey east. In launching their Holy War and maintaining its momentum over two centuries, the Crusaders showed the world the devastating effect of forcibly dividing the world along the lines of religion. "

― , The Crusades: A History From Beginning to End