He then fortified the walls , and constructed a customs office , quarantine , and check point , as well as placing a garrison of troops there .
Within a few years , Sultan Mehmed drove the Genoese out .
Sultan Mehmed then fortified the walls , and constructed a customs office , quarantine , and check point , as well as placing a garrison of troops there .
Within a few years , Sultan Mehmed drove the Genoese out .