This is a timeline of the rise and fall of Sub-Saharan Africa's once powerful kingdoms from the 7th to the 19th centuries. Trade was carried on by boat and camel caravan in resources such as gold, ivory, and salt, as well as enslaved people. These kingdoms - including the Aksum (Ethiopia), Ghana, Great Zimbabwe, Mali, Benin, and Songhai empires - were ultimately conquered by European nations in the Scramble for Africa in the 19th century, with only Liberia and Ethiopia remaining independent.