Qawsun had joined Tulunbay 's retinue as a traveling merchant .
Once Qawsun arrived in Egypt , Qawsun moved to the Mamluk Sultanate 's capital , Cairo , to sell Qawsun 's leather wares .
Qawsun had joined Tulunbay 's retinue as a traveling merchant , and once he arrived in Egypt , he moved to the Mamluk Sultanate 's capital , Cairo , to sell his leather wares .