 In September 1183 , construction of the Cairo Citadel began under Saladin 's orders . According to al @-@ Maqrizi , Saladin chose the Muqattam Hills to build the citadel because the air there was fresher than anywhere else in the city , but its construction was not so much determined by the salubrious atmosphere ; rather it was out of defensive necessity and example of existing fortresses and citadels in Syria . The walls and towers of the northern section of the citadel are largely the works of Saladin and al @-@ Kamil . Two of Saladin 's towers were totally encased by semi @-@ circular units . Al @-@ Kamil completed the citadel ; he strengthened and enlarged some of the existing towers , and also added a number of square towers which served as self @-@ contained keeps . According to Richard Yeomans , the most impressive of al @-@ Kamil 's structures was the series of massive rectangular keeps which straddled the walls of the northern enclosure . All of al @-@ Kamil 's fortifications can be identified by their embossed , rusticated masonry , whereas Saladin 's towers have smooth dressed stones . This heavier rustic style became a common feature in other Ayyubid fortifications , and can be seen in the Citadel of Damascus and that of Bosra in Syria . 
