Fortified-town-building culture of the Lake Chad basin (Chari river floodplain), known for terracotta and bronze work; predates and overlaps with the rise of Kanem-Bornu (already tracked in canonical from 700), eventually absorbed or displaced by Kanem-Bornu expansion and Sao-descended peoples such as the Kotoko.
Declined under pressure from Kanem and was absorbed by the rising Kotoko and neighboring peoples by around 1600.
Broad continental history noting the Sao culture's place among Lake Chad-basin Iron Age societies.