 When Krak des Chevaliers was remodelled in the 13th century , new walls surrounding the inner court were built . They followed the earlier walls , with a narrow gap between them in the west and south which was turned into a gallery from which defenders could <unk> missiles . In this area , the walls were supported by a steeply sloping glacis which provided additional protection against both siege weapons and earthquakes . Four large , round towers project vertically from the glacis ; they were used as accommodation for the Knights of the garrison , about 60 at its peak . The southwest tower was designed to house the rooms of the Grand Master of the Knights Hospitaller . Though the defences which once crested the walls of the inner wards no longer survive in most places , it seems that they did not extend for the entire circuit . <unk> were absent from the southern face . The area between the inner court and the outer walls was narrow and not used for accommodation . In the east , where the defences were weakest , there was an open cistern filled by an <unk> . It acted both as a <unk> and water supply for the castle . 
