 In 1173 , Saladin sent Turan @-@ Shah to conquer Yemen and the Hejaz . Muslim writers Ibn al @-@ Athir and later al @-@ Maqrizi wrote that the reasoning behind the conquest of Yemen was an Ayyubid fear that should Egypt fall to Nur al @-@ Din , they could seek refuge in a faraway territory . In May 1174 , Turan @-@ Shah conquered <unk> from a Kharijite dynasty and executed its leader Mahdi Abd al @-@ Nabi , and later that year Aden was taken from the Shia Banu Karam tribe . Aden became the principal maritime port of the dynasty in the Indian Ocean and the principal city of Yemen , although the official capital of Ayyubid Yemen was Ta <unk> . The advent of the Ayyubids marked the beginning of a period of renewed prosperity in the city which saw the improvement of its commercial infrastructure , the establishment of new institutions , and the minting of its own coins . Following this prosperity , the Ayyubids implemented a new tax which was collected by galleys . 
