The Bantu Expansion stands for the concurrent dispersal of Bantu languages and Bantu-speaking people from an ancestral homeland situated in the Grassfields region in the borderland between current-day Nigeria and Cameroon. During their initial migration across most of Central, Eastern, and Southern Africa, which took place between approximately 5,000 and 1,500 years ago, Bantu speech communities not only introduced new languages in the areas where they immigrated but also new lifestyles, in which initially technological innovations such as pottery making and the use of large stone tools played an important role as did subsequently also farming and metallurgy. Wherever early Bantu speakers started to develop a sedentary way of life, they left an archaeologically visible culture. Once settled, Bantu-speaking newcomers strongly interacted with autochthonous hunter-gatherers, as is still visible in the gene pool and/or the languages of certain present-day Bantu speech communities. The driving forces behind what is the principal linguistic, cultural, and demographic process in Late Holocene Africa are still a matter of debate, but it is increasingly accepted that the climate-induced destruction of the rainforest in West Central Africa around 2,500 years ago gave a boost to the Bantu Expansion.
States that flourished in the area immediately south of the Zambesi River from the 15th to the 19th centuries were ruled by Karanga dynasties and were the cultural heirs of Great Zimbabwe. The most important of these states was Mokaranga, whose rulers bore the title of Monomotapa. Other important states—Teve, Manica, Barue, and Butua—all depended on the mining and trading of gold. Commerce was conducted at fairs attended by merchants from coastal towns such as Sofala and Chibuene, which were part of the networks of Indian Ocean commerce. At the beginning of the 16th century this trade attracted Portuguese traders who visited the fairs. In the 17th century, the Portuguese gradually expanded their presence through the institution of the prazos, whose owners acquired jurisdiction over extensive areas formerly ruled by the Karanga. The Portuguese were expelled from the Zimbabwe plateau in the 1690s and were succeeded by the Rosvi, another Karanga ruling elite. These states were devastated by droughts from the 1790s to the 1830s. All of them experienced civil wars before they were conquered by the Ngoni, who established the kingdom of Gaza, which covered the whole area south of the Zambesi as far as the Limpopo River until the time of the Scramble for Africa. Some of the old Karanga states, notably Manica and Barue, survived as tributaries of the Gaza state.