At the beginning of the 20th century there were four white South African colonies. Two of these, Transvaal and Orange Free State, were governed by European populations of predominantly Dutch origin, known as Afrikaners or Boers, while Natal and Cape Colony were ruled by British settlers. After the Boer War the colonies were united to form the Union of South Africa (1910).

South Africa was a self-governing dominion within the British Empire. A British governor general was nominal head of state but power rested with an Executive Committee headed by General Luis Botha. In South Africa native peoples and women were barred from public office.

The South African Army was formed in 1912. It had five regular mounted regiments and a small artillery section. Conscription was also introduced in 1912 and half of the European males aged 16 to 25 were drafted by lots into the Active Citizen Force (ACF).