The answer to this question would be USE COINS. The people of Aksum in the sub-Saharan Africa were the first ones to use coins and these were called as Aksumite coins with Aksumite currency. Given this historical event, it was believed that the people of Aksum are literate and these coins were being used in international trade. The Aksumite coins are made of gold or silver and in the coin is the name of King Endybis.