<P> The Union of South Africa (Dutch: Unie van Zuid - Afrika, Afrikaans: Unie van Suid - Afrika pronunciation (help info)) is the historic predecessor to the present - day Republic of South Africa . It came into being on 31 May 1910 with the unification of four previously separate British colonies: the Cape, Natal, Transvaal and Orange River colonies . It included the territories formerly part of the Boer republics annexed in 1902, the South African Republic and the Orange Free State . </P> <P> Following the First World War, the Union of South Africa was granted the administration of South West Africa (formerly a German colony and today the sovereign state of Namibia) as a League of Nations mandate, which became treated in most respects as if it were another province of the Union, but never was formally annexed . </P> <P> The Union of South Africa was a self - governing autonomous dominion of the British Empire . Its independence from the UK was confirmed in the Balfour Declaration 1926 and the Statute of Westminster 1931 . It was governed under a form of constitutional monarchy, with the Crown represented by a governor - general . The Union came to an end with the enactment of a new constitution on 31 May 1961, by which it became a republic and temporarily left the Commonwealth, under the new name Republic of South Africa . </P> <P> Unlike Canada and Australia, the Union of South Africa was a unitary state, rather than a federation, with each colony's parliaments being abolished and replaced with provincial councils . A bicameral parliament was created, consisting of a House of Assembly and Senate, and its members were elected mostly by the country's white minority . During the course of the Union the franchise changed on several occasions always to suit the needs of the government of the day . Parliamentary supremacy was a convention of the constitution, inherited from the United Kingdom; save for procedural safeguards in respect of the entrenched sections of franchise and language, the courts were unable to intervene in Parliament's decisions . </P>

Which european nation controlled the union of south africa
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