Question: what was south africa called before it became a republic
Answer: Following the defeat of the Boers in the Anglo - Boer or South African War ( 1899 -- 1902 ) , the Union of South Africa was created as a dominion of the British Empire in terms of the South Africa Act 1909 , which amalgamated the four previously separate British colonies : Cape Colony , Natal Colony , Transvaal Colony and Orange River Colony .