Rwanda
The Banyarwanda are the Bantu people of the mountainous country around Lake Muhazi, united by the Kinyarwanda language and traditionally divided not into separate peoples but into three social categories: the farming Hutu, the cattle-keeping Tutsi and the hunter-gatherer Twa, whose clans cut across all three.
Bantu farmers had cleared these hills by about 1000, and waves of pastoral Tutsi entered from the north between the fifteenth and sixteenth centuries. From the fourteenth or fifteenth century the clans coalesced into kingdoms; the Gasabo chiefdom beside Lake Muhazi grew into the Kingdom of Rwanda under its Nyiginya dynasty.
Around 1600 an invasion by the Banyoro drove its kings westward, but Ruganzu Ndori rebuilt the state from Nyanza, and in the seventeenth century his successors subdued outlying Hutu communities. Conquered populations were absorbed as Banyarwanda, and the realm became one of the most centralized monarchies of the Great Lakes, its mwami, or king, ruling through appointed chiefs rather than hereditary lineages.