Name three cities in the sudan region of west africa that prospered as a result of the reopening of the trans-saharan trade routes in the eighth century

There are several states that flourished as a result of trade between the Sahel across the Sarah with north African crab traders and the Levant world. these city states included Timbuktu that had the earliest form of university in the world , GAO,Djene. The city states often levied trade and were located along the trade routes.