When Britain declared war on Germany on the 4th of August 1914, South African Prime Minister Louis Botha cabled London, acknowledging South Africa’s constitutional obligation to support Britain. He offered to release the garrisons of British troops which had remained in South Africa after Union at his request and to replace them by mobilising the South African Defense Force.

Britain accepted, and further requested to mount an attack to seize the coastal wireless stations at Luderitzbucht and Swakopmund in the neighbouring German Protectorate of South West Africa (Namibia). Botha cabled, agreeing to do this, though he did not make his undertaking public at the time.

After Botha announced in Parliament the plan to invade South West Africa, which was approved by 92 vote to 12, things began to happen fast. The well-loved Boer hero, General Koos de la Rey died tragically, accidentally shot by a police patrol on the look-out for a gang of dangerous criminals. Many believed that the Government had engineered his death deliberately because of his opposition to the invasion of South West Africa.

Apart from the small South African force which had occupied Luderitzbucht in September, the rebellion had delayed the attack on South West Africa. Swakopmund was occupied in January 1915, and the main advance in three columns began in March. Botha was able to employ a white force of over 40 000 men supported by a black labour contingent of 33 546. The Germans with potential forces, including civilians, of 9 000 men did not have them all under arms. The real enemies were not these heavily outnumbered German forces, but the vastness of the country, the lack of water and communications. Botha showed great skill and energy in his conduct of the campaign and the last of the enemy surrendered on the 9th of July 1915. Only 114 South Africans had been killed or died of wounds and another 153 succumbed to disease or accident. The black contingent was praised for its service and good conduct.

Thousands of white South Africans left the country independently to join the British forces in Europe. Others volunteered for the First South African Brigade which embarked for England late 1915. Yet another force of volunteers went to join the British and Indian troops for the invasion of German East Africa (Burundi, Rwanda and Tanzania), where General Smuts took command. Like the South West Africa force this was supported by a black labour contingent which numbered 18 000. It was to be a long and arduous campaign against the German commander, General von Lettow-Vorbeck, in a wilderness where tropical diseases claimed many victims.

By the beginning of 1916 the war in Western Europe had reached a stalemate. The great German offensive on 1914, which overran Belgium and went deep into France had been checked by the Allies in Flanders and on the Marne. Holding almost all of Belgium and a tenth of France the Germans faced the Allies from a line of trenches, fortifications and outposts that ran some 450 miles from the coast of Belgium to the borders of Switzerland. French and British attacks in 1914 and 1915, sent in piecemeal, melted away before massed artillery, machine-guns, and barbed wire, achieving little success for heavy losses of life.

Much of Britain's small professional army was destroyed in the battle of 1914 and she began to raise a volunteer force of a million men. The Military Service Act, passed in February 1916, required all able-bodied men from the age 18 to 41 to register for service. The Continental powers already had universal conscription. As plans were made for major offensives 1916, it was clear that this war would require a use of men and material on a scale unprecedented in history.

In attacking the French positions round the fortress of  Verdun in February 1916, a battle which was to last intermittently until December of that year, the Germans were at least in some part actuated by the idea of forcing the French army to bleed itself to death in defense. The Allies, too, were coming to think in terms of a war of attrition in despair of a decisive breakthrough to victory. If the enemy could not be beaten, perhaps he could be forced to come to terms through loss of manpower and could be outlasted.

The great Franco-British offensive on the Somme began on the 1st of July 1916, with the loss of nearly 60 000 British troops on the first day for negligible gain of ground. It was to last until November. The first South African Brigade, all white troops, played its role there two weeks later. They were ordered to capture and hold Delville Wood and in six days and five nights of fierce fighting they obeyed their orders. The Brigade numbered 3153 when the attack commenced. Only 43 came out of what was left of the wood for the first roll-call when they were relieved. The final muster on the 21st of July was 780. Of the casualties 766 were killed or died of wounds. The Brigade was greatly praised for its courage and endurance.

The Dominions of the British Empire, Australia, Canada, New Zealand and South Africa, had already contributed large numbers of volunteer troops in relation to their populations. Not only fighting troops to carry weapons and man the trenches were required, but also labourers to work in the dockyard and railheads, work quarries, forestry, road building and maintenance, dig behind the lines and manhandle supplies and munitions. These were recruited from men considered unfit, for various reasons, to serve as combatants. One disqualification for combat troops was skin colour. According to British and white South Africans standards of the day the idea of using black troops to fight against white troops was considered unwise, even repugnant and very few black troops had been enlisted as combatants in the Anglo-Boer War.

While the Somme battle was still in progress and South Africa mourned its dead of Delville Wood the British Government asked the South African Prime Minister, in an exchange of correspondence not made public, to recruit 10 000 black troops to serve in labour battalions under British command in France.

On the 7th of September 1916, Prime Minister Botha agreed to the British request. On the following day, he made a public announcement to this effect, and recruitment of the South African Native Labour Contingent began.