The mysteriousness of such knowledge might be reinforced in societies where secret associations had a monopoly of spiritual activity. Taking captives was a major objective in war, with most of the individuals thus enslaved being women or children. First, the African languages were solidly rooted: three languages (Zulu, Xhosa, and Sotho) are spoken by over two million people each, and the first two are mutually understandable. The land, much of which is hills and plateaux, is covered with grasslands, with some sub-tropical forests on the coast. Ancient Africa - Social Structure The pastoralists tended to inhabit the desert and Sahel regions, leaving most of the savannah and forest regions to the farmers. Ancient Mali Social Hierarchy The Mali Empire was an ancient empire in West Africa between c.1230 to c.1600. The main city, Adulis, at the time was a very important port. The General History of Africa ( Ki-Zerbo, et al. Sometimes these were royal kinsmen or aristocrats, at other times royal slaves completely dependent upon the king for his authority. Starting perhaps as just one settlement, they would expand outwards into the bush over time as they cleared new land and established new settlements. The ancientness of the continents rocks, whose minerals have leeched out over the aeons, mean that the soil is generally of a poor quality, posing challenges for farmers. YjU5YTA2MjA2ZTZjNTRkNmQ0OTBmNzIzM2EzZTIyZWFlMDBlMGViZTQzMDMw Growth of the Axum Kingdom. Many captives were sold on to other peoples; there was an active slave trade in Africa. Male children could be trained up to become administrators in the royal service, and in some states filled the most responsible positions at court: their lowly social status was thought to act as a check to their ambitions and a guarantee of their loyalty (though a chief slave may have usurped the Mali throne in 1357). Pastoralists had come down the Nile Valley and then spread out across the grasslands of Africa, down as far as the Great Lakes region of central Africa.