The Boer War was fought from 11 October 1899 until 31 May 1902 between the United Kingdom of Great Britain and Ireland and the South African Republic (Transvaal Republic) and the Orange Free State. The British war effort was supported by troops from several regions of the British Empire, including Southern Africa, the Australian colonies, Canada, Newfoundland, British India, and New Zealand. The war ended in victory for the British and the annexation of both republics. Both would eventually be incorporated into the Union of South Africa in 1910. The Boer War was the harbinger for a new type of combat which would persevere throughout the twentieth century, guerrilla warfare.