The narrative, which makes excellent use of the first-hand diaries and reports, including those of Rider Haggard's brother Andrew and of Father Ohrwalder (the Austrian missionary who spent ten years of captivity in the Mahdi's camp), brilliantly describes the growth and strength of the Mahdist movement and the extraordinary devotion and discipline of the Dervish troops. Facing such opponents with stoic endurance were the British, Egyptian and Sudanese Negro soldiers, and the resulting military engagements evoked amazing feats of courage and derring-do on both sides. The Dervish Empire outlasted the Mahdi by thirteen years. It ended in the battle of Omdurman and Kitchener's reconquest of the Sudan, which was well supported by Reginald Wingate's military intelligence operations. It lasted a comparatively brief span of time, but it had been established at the expense not only of the neighboring Abyssinians but also of the European white man, at a time when Britain was approaching the zenith of its imperial power.