Ghana, Mali, and Songhai were three of the greatest western African trading states. Beginning with Ghana as early as 300 c.e. and ending with the conquest of the Songhai by Morocco in the 16th century c.e., they dominated the trade of gold, salt, and merchandise between North Africa and sub-Saharan Africa. Arab scholars and merchants as far away as Baghdad marveled at the wealth of these African states. The geographer al-Ya’qubi claimed that "gold is found in the whole of this country." But the trade of gold and salt was not the only basis for West African civilization.