title: History of South Africa
context: 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. The country became a self-governing nation state within the British Empire, in 1934 following enactment of the Status of the Union Act. The dominion came to an end on 31 May 1961 as the consequence of a 1960 referendum, which legitimised the country becoming a sovereign state named Republic of South Africa. A republican constitution was adopted.
question: When did South Africa become an independent country?
answers: 31 May 1961