The South African Infantry Corps is the largest combat corps within the South African Army. The unit originated as the Infantry Branch of the Union Defence Forces in 1913. In 1915, the defence forces established the South African Overseas Expeditionary Force for war service outside southern Africa. It included the South African Infantry, comprising twelve battalions, and the Cape Corps, comprising two battalions of Coloured volunteers. These units were disbanded in 1919. The Infantry Branch was enlarged in 1934, and the mounted rifles regiments were converted to infantry in 1935.