The Union of South Africa (now the Republic of South Africa) was established in 1910, after a period of reconstruction following the Anglo-Boer War of 1899-1902. Unlike other African colonies, South Africa had a large European population, making up about 20% of the whole, but it was deeply divided between English and Afrikaner communities. In 1914, South African support for the war effort was by no means straightforward.

German South West Africa

CO 633/88

Namutoni Fort, South West Africa, 1917. CO 633/88

In August 1914, the British government asked the Union to invade the German colony of South West Africa (now Namibia) to the north and to capture radio stations helping the German Navy. If the Union government refused to agree to the request, imperial forces would be used instead.

The Prime Minister, Louis Botha, and Defence Minister, Jan Smuts, both Afrikaner veterans of the Anglo-Boer War, fully supported the Union’s participation. This was passed by the South African parliament on 12 September 1914.  South African troops would carry out the invasion themselves, leaving the British government free to withdraw its own forces to fight in Europe.  

The South African forces invaded across the Orange River border in September 1914, but met with some setbacks. In February 1915, Louis Botha took charge of a second invasion, using the South African enclave of Walvis Bay as a base. After that, the South Africans made rapid progress, capturing the capital, Windhoek, in May 1915.

Other South African units lead by Jan Smuts landed at Luderitz Bay to the south, while a further contingent invaded across the border. The German forces under Governor Theodore Seitz surrendered at Khorab in the northeast of South West Africa in July 1915.

The generous terms of surrender granted to the Germans in South West Africa reflected the ambivalence of white South Africans to the war. German reservists were allowed to return to their homes and German colonists kept their property.

After the war, the League of Nations granted the Union authority to administer South West Africa (ADM 123/144, CAB 44/2, CAB 45/112, DO 119/893895, CO 879/119/2).


CO 633/59/14

Report on the rebellion, South Africa, 1915. CO 633/59/14

Afrikaners were divided on the question of South African support for the war.  Many within the South African army were opposed to it and some saw an opportunity for Afrikaners to seize independence. A number of Afrikaner generals and leaders, most notably Christiaan Frederick Beyers, commander of the defence force, and Koos de la Rey, politician and hero of the Anglo-Boer War, joined together to lead a rebellion. Manie Maritz, the commander of the South African troops in the Northern Cape, defected to the Germans.  

The outcome was a brief insurgency, which was soon defeated once martial law was declared in October 1914. De la Rey was killed at road block, while Beyers drowned during an attempt to escape across the Vaal River. The Union government appointed a commission of enquiry into the rebellion. It needed to unite English and Afrikaner South Africans around the war effort and took a conciliatory approach. As a result, most rebels served only short sentences (CO 537/565568; CO 537/570; CO 633/59/14; CO 633/64/1; DO 119/899).  

East Africa and Europe

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South African gunners crossing Ruhuhu River near Weidhafen, 1916-1918. CO 1069/133

Towards the end of 1915, the British Cabinet decided to capture German East Africa and South African troops played a key role in the East African campaign which followed. When the invasion of German East Africa began in February 1916, a number of South African units, including horse, infantry, artillery and the Cape Corps, which was made up of soldiers of mixed race, were already present in East Africa.

On 12 February 1916, the South Africans, together with a regiment of the British Indian Army, the 130th Baluchis, carried out an attack on the German lookout post at Salaita Hill, just across the border near Kilimanjaro. The position was heavily fortified and the attackers came under fire from German artillery. They were forced to retreat, suffering 172 casualties (WO 32/5820).

Shortly after the battle of Salaita Hill, the South African General Jan Smuts arrived in East Africa to take control of the combined imperial forces (WO 339/82390). He successfully cleared the Kilimanjaro area but the German forces under General von Lettow-Vorbeck proved to be elusive. They tended to avoid full confrontation in an attempt to tie up British forces and prolong the campaign. Nevertheless, South African units took part in some fierce fighting as they attempted to capture German positions near the border with British East Africa.

In the early months of the campaign, during the bid to capture Taveta near Kilimanjaro, the 2nd South African Infantry Brigade took part in hand-to-hand fighting near Latema. Following a full night’s march, the 1st South African Horse regiment swam the Pangani River and attacked the German forces from the rear. Having taken Kahe Hill they withstood vigorous counter attacks. In April, another South African, General Jacob van Deventer, commander of the 2nd Division, led a 140-mile march on the strategic point at Kondoa Irangi, south west of Kilimanjaro. His troops then repulsed attacks led by Von Lettow-Vorbeck (WO 95/5345, WO 95/5347).

A number of South Africans served with great distinction. On 24th August 1916, Captain William Anderson Bloomfield, of the 2nd South African Mounted Brigade, earned the Victoria Cross when he risked heavy machine gun fire to rescue an injured soldier who had been left behind during an evacuation (WO 98/8/320).

From the end of 1916, South African troops were withdrawn from East Africa for deployment in Europe. Smuts left in January 1917 to become a member of the British War Cabinet and was replaced Major-General A R Hoskins and then by General van Deventer, who saw the campaign through until its conclusion in November 1918.

South African troops played an important role on the Western Front. By June 1915, the Union government had decided that troops would be sent to Europe. It committed the 1st South African Brigade, consisting of four infantry battalions and a number of support units, including batteries of artillery and a field ambulance unit. In January 1916, the South African Brigade was send to Egypt. It saw action in February at the Battle of Agagia, assisting in the defeat of a rebellion in north western Egypt, near the border with Libya.   

They left for France in April 1916, destined to fight in the battle of the Somme in July. They suffered heavy casualties at Delville Wood in July 1916, where over two thirds of the 3,000 South Africans who fought were either injured or killed. The Brigade remained on the western front until the end of the war (WO 95/4448).

Black South Africans played an important part in the war. In 1916, Prime Minister Louis Botha agreed with the British government that the Union would recruit black South Africans for labour, but not combat roles. The South African Native Labour Corps was established in September 1916, and 25,000 had joined by the beginning of 1918. Members of the Corps worked as labourers, dockers, road builders and on railways in western Europe and in East Africa.

In February 1917, the merchant ship SS Mendi was carrying members of the 5th Battalion of the Corps to France. On 21 February the Mendi was off the Isle of White in thick fog. She was struck by another merchant ship the SS Darro and sank with the loss of over 600 black South Africans. In spite of their important work, the rank and file of the South African Native Labour Contingent never received war medals or ribbons (WO 107/37).

The South African military authorities raised two volunteer battalions of the historic Cape Corps, which were made up of soldiers of mixed race. The Corps fought a number of campaigns, and most famously they won the Battle of Square Hill against the Turkish army during September 1918 in the Sinai and Palestine campaign (WO 95/4632).  

An estimated 250,000 South Africans served in various military units during the First World War. They suffered approximately 19,000 casualties, with over 12,000 deaths.

Key figures

General Jan Christiaan Smuts

General of the South African Army and member of the Imperial War Cabinet (1914-1919)

General Louis Botha

Prime Minister of South Africa (1910-1919)

General Jacobus (Koos) de la Rey

Senator, Union of South Africa (1910-1914)

Christiaan Frederick Beyers

Christiaan Frederick Beyers

Politician and leader of the Boer rebels

Key documents

CO 1069/133

SAMR guns passing over native bridge, Kenya, 1916-1918. CO 1069/133

  • The campaign in German South West Africa, 1914-1916 ADM 123/144
  • Operations in the Union of South Africa and German South-West Africa; narrative of events, August 1914 - August 1915 CAB 44/2
  • The campaign in German South West Africa: narrative of events with composition of forces involved, 1914-1915 CAB 45/112
  • Military operations in German South West Africa, 1914-1915 DO 119/893-895
  • Reports on the administration of the protectorate of South West Africa, 1916-1916 CO 879/119/2
  • Rebellion in Transvaal, 1914 CO 537/565-568
  • Rebellion in Transvaal, 1914 CO 537/570
  • Union of South Africa, Senate, 1915: Report on the outbreak of the rebellion and the policy of the government with regard to its suppression, 1915 CO 633/59/14
  • Report of the Select Committees on Rebellion, 1915 CO 633/64/1
  • Rebellion in South Africa, 1914 DO 119/899
  • Report by Lieutenant General J Smuts, commander-in-chief East Africa force, on military operations with maps, 1916 WO 32/5820
  • Long Service Papers. Lieutenant-General Jan Christiaan Smuts, 1914-1922 WO 339/82390
  • War diaries 2, East African Division WO 95/5345
  • War diaries 3, East African Division, 1917-1918 WO 95/5347
  • Medal listing of Bloomfield, William Anderson, 1916 WO 98/8/320
  • Delta and Western Force (formerly Western Frontier Force) WO 95/4448
  • Work of the labour force during the war: report 1919 WO 107/37
  • 1st Battalion Cape Corps, March-June 1918 WO 95/4632