sentences:  The Hausa city states emerged as southern terminals of the Trans-Saharan caravan trade.Like other cities such as Gao and Timbuktu in the Mali Empire, these city states became centres of long-distance trade.Hausa merchants in each of these cities collected trade items from domestic areas such as leather, dyed cloth, horse gear, metal locks and Kola nuts from the rain forest region to the south through trade or slave raiding, processed (and taxed) them and then sent them north to cities along the Mediterranean.