As part of an attempt to display its loyalty to the British empire and, perhaps more importantly, enlarge its own sphere of influence on the African continent, South Africa sends troops to occupy Swakopmund, a seaside town in German-occupied Southwest Africa (modern-day Namibia).
When war broke out in 1914, South African Prime Minister Louis Botha immediately pledged full support for Britain, antagonizing a portion of South Africa's ruling Afrikaner (or Boer) population, who were still resentful of their defeat, at the hands of the British, in the Boer War of 1899-1902.
That conflict had pitted the Boers, descendants of South Africa's Dutch settlers who controlled two republics—the gold-rich Transvaal and the Orange Free State—against the colonial armies of Great Britain. A stiff Boer resistance, including an extensive campaign of guerrilla warfare, had ultimately been repressed by brutal methods—including concentration camps—introduced by the British commander in chief, Lord Horatio Herbert Kitchener (who later became Britain's minister of war). Under the terms of the Treaty of Vereeniging, which ended the Boer War in 1902, the Boer republics were granted eventual self-government as colonies of the British empire. They received their own constitutions in 1907 and in 1910 the British Parliament's South Africa Act established the Union of South Africa as a united self-governing dominion of the British empire. Botha, the leader of the South African Party, became its first head of government.
In 1914, Botha and Minister of Defense Jan Smuts, both generals and former Boer commanders, were looking to extend the Union's borders further on the continent. Invading German Southwest Africa would not only aid the British—it would also help to accomplish that goal. The plan angered some Afrikaners, who were resentful of their government's support of Britain against Germany, which had been pro-Boer in their war against the British. Several major military leaders resigned over their opposition to the invasion of the German territory and open rebellion broke out in October 1914. It was quashed in December and the conquest of Southwest Africa, carried out by a South African Defense Force of nearly 50,000 men, was completed in only six months.
On July 9, 1915, Germans in Southwest Africa surrendered to South African forces there; 16 days later, South Africa annexed the territory. At the Versailles peace conference in 1919, Smuts and Botha argued successfully for a formal Union mandate over Southwest Africa, one of the many commissions granted at the conference to member states of the new League of Nations allowing them to establish their own governments in former German territories. In the years to come, South Africa did not easily relinquish its hold on the territory, not even in the wake of the Second World War, when the United Nations took over the mandates in Africa and gave all other territories their independence. Only in 1990 did South Africa finally welcome a new, independent Namibia as its neighbor.