The most famous Retief in South African history is Piet Retief — the Voortrekker leader murdered by Dingane at uMgungundlovu in 1838.
The family is not descended from him. But it does share his stamvader. Both lines run back to François Retif (b. Mer, 1663), and both diverge at Gen 2: this family runs through François’s son Paul; the Piet Retief branch runs through a separate son. The same Huguenot ship, the same Reformed temple at Mer that burned in 1685, the same passage to the Cape in 1688 — and then the two branches walked into entirely different histories.