 Between 1142 and 1170 the Knights Hospitaller undertook a building programme on the site . The castle was defended by a stone curtain wall studded with square towers which projected slightly . The main entrance was between two towers on the eastern side , and there was a postern gate in the northwest tower . At the center was a courtyard surrounded by vaulted chambers . The lay of the land dictated the castle 's irregular shape . A site with natural defences was a typical location for Crusader castles and steep slopes provided Krak des Chevaliers with defences on all sides bar one , where the castle 's defences were concentrated . This phase of building was incorporated into the later castle 's construction . 
 Between 1142 and 1170 the Knights Hospitaller undertook a building programme on the site . The castle was defended by a stone curtain wall studded with square towers which projected slightly . The main entrance was between two towers on the eastern side , and <a href='dey_it' title='1'><mark>there</mark></a> was a postern gate in the northwest tower . At the center was a courtyard surrounded by vaulted chambers . The lay of the land dictated the castle <a href='null_genetive' title='2'><mark>'s</mark></a>irregular shape . A site with natural defences was a typical location for Crusader castles and steep slopes provided Krak des Chevaliers with defences on all sides bar one , where the castle <a href='null_genetive' title='3'><mark>'s</mark></a>defences <a href='uninflect' title='4'><mark>were</mark></a> concentrated . This phase of building was incorporated into the later castle <a href='null_genetive' title='5'><mark>'s</mark></a>construction . 
Between 1142 and 1170 the Knights Hospitaller undertook a building programme on the site . The castle was defended by a stone curtain wall studded wit square towers which projected slightly . da main entrance was between 2 towers on the eastern side , and it was a postern gate in tdanorthwest tower . At the center was a courtyard surrounded by vaulted chambers . The lay of thdaand dictated the castle  irregular shape . A site with natural defences was a typical location for Crusader castles and steep slopes provided Krak des Chevaliers with defences on all sides bar one , where thedastle  defences was concentrated . dis phase of building was incorporated into the later castle  construction .