Political map of Sub-Saharan Africa 31 May 1910 (Union of South Africa): In the wake of the Second Boer War (1899-1902), the British encouraged a tighter union between the old British colonies of the Cape of Good Hope and Natal and the two former Boer republics of Transvaal and Orange River Colony. This vision was realized in 1910, when all four colonies united to form the Union of South Africa. A self-governing dominion, this new South Africa was run almost exclusively by its White minority - in particular the Boers/Afrikaners, who were more numerous than the English-speaking Whites.