structural:expansion
From the 11th century to 17th century

Between the 11th and 16th centuries, powerful Bantu-speaking states on a scale larger than local chiefdoms began to emerge. Notable early kingdoms include the Kingdom of the Kongo in present day Angola and the Democratic Republic of the Congo, the Bunyoro Kitara Kingdom in the Great Lakes region, the Kingdom of Mapungubwe (c.1075–c.1220) in present day South Africa, and the Zambezi River, where the Monomatapa kings built the Great Zimbabwe complex. The Swahili city-states were also established early in this period. These include sultanates based at Lamu, Mombasa, Kilwa, Pate and Malindi. The Swahili traded with the inland kingdoms, including Great Zimbabwe. Such processes of state-formation occurred with increasing frequency from the 16th century onward. They likely resulted from denser population, which led to more specialised divisions of labour, including military power, while making outmigration more effortful. Other factors promoting state-formation were increased trade among African communities and with European and Arab traders on the coasts, technological innovations in economic activity, and new techniques in the political-spiritual ritualisation of royalty as the source of national strength and health. Other inland centres established during this phase of expansion include Bigo bya Mugenyi in Uganda, Thimlich Ohinga in Kenya and the Kweneng' Ruins in South Africa.