 As Chief of Staff (1900–1902) in the Second Boer War he played a key role in Lord Roberts' conquest of the Boer Republics, then succeeded Roberts as commander-in-chief – by which time Boer forces had taken to guerrilla fighting and British forces imprisoned Boer civilians in concentration camps.His term as Commander-in-Chief (1902–09) of the Army in India saw him quarrel with another eminent proconsul, the Viceroy Lord Curzon, who eventually resigned.Kitchener then returned to Egypt as British Agent and Consul-General ("de facto" administrator).