Boers opposed British ambitions in South Africa. The British Empire and the two independent Boer republics had fought two wars. The First Anglo-Boer War happened between 1880 and 1881, while the Second Anglo-Boer War occurred between 1899 and 1902.
Further reading:
www.spartacus.schoolnet.co.uk/WARboer.htm
www.bbc.co.uk/history/british/victorians/boer_wars_01.shtml