Excerpts from Books and Wikipedia
"When hundreds of thousands of Englishmen poured into the mining towns of Rhodesia, the Transvaal, and Bechuanaland in the 1880s, they overwhelmed the Boer population, making conflict inevitable. The president of the Transvaal, Paul Kruger, pressurized the foreigners by levying discriminatory taxes on them and curbing their political rights." [DK Timelines, p. 382]
"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 brought them to terms. . . . The onward marches of the British Army, well over 400,000 men, were so overwhelming that the Boers did not fight staged battles in defence of their homeland. The British quickly seized control of all of the Orange Free State and Transvaal, as the civilian leadership went into hiding or exile. In conventional terms, the war was over. The British officially annexed the two countries in 1900. . . . The Boers refused to surrender. They reverted to guerrilla warfare under new generals Louis Botha, Jan Smuts, Christiaan de Wet and Koos de la Rey. " [Wikipedia]