Southern Nilotic ancestors of the Kalenjin move into the Rift highlands contested
The peoples later grouped as Kalenjin descend from Southern Nilotic herders who spread from the South Sudan and Ethiopia borderlands into the highlands of East Africa. Linguists and archaeologists place this movement in the long period often called the African Classical Age, roughly the first millennium BCE into the early centuries CE. The migrants mixed with earlier Cushitic-speaking and hunter-gatherer populations already in the region, so the modern cluster grew out of blending rather than a single pure stock.