 After acquiring the site in 1142 , they began building a new castle to replace the former Kurdish fortification . This work lasted until 1170 , when an earthquake damaged the castle . An Arab source mentions that the quake destroyed the castle 's chapel , which was replaced by the present chapel . In <unk> the Crusaders emerged victorious over Nur ad @-@ Din in the Battle of al @-@ <unk> near Krak des Chevaliers . 
