The Second Boer War, also known as the Boer War, the Anglo-Boer War, or the South African War, was fought between the British Empire and two independent Boer states, the South African Republic and the Orange Free State, over the Empire's influence in South Africa. The trigger of the war was the discovery of diamonds and gold in the Boer states. Initial Boer attacks were successful, and although British reinforcements later reversed these, the war continued for years with Boer guerrilla warfare, until harsh British counter-measures including a scorched earth policy brought the Boers to terms.
A few British colonies existed nearby. The Boer War can be understood to have formally started with well-armed Boer irregulars and militia striking first, against towns in those colonies. They besieged Ladysmith, Kimberley, and Mafeking in early 1900, and winning important battles at Colenso, Magersfontein and Stormberg. Surprised, under-prepared, and overconfident, the British responded bringing in modest numbers of soldiers and fought back with little initial success. Leadership and tactics changed when General Redvers Buller was replaced by Lord Roberts and Lord Kitchener.