Their numbers at first did not exceed 5,000; but as more towns were taken and more slaves were turned into soldiers they increased, until at one time they reached the formidable total of 15,000 men.  During the siege of Khartoum the black riflemen distinguished themselves by the capture of Omdurman fort, but their violent natures and predatory instincts made them an undesirable garrison even for the Dervish capital, and they were despatched under their general to Kordofan, where they increased their reputation by a series of bloody fights with the Nubas, an aboriginal mountain people who cared for nothing but their independence.

At the end of June Abu Anga reached Omdurman with an army variously estimated at from 22,000 to 31,000 men, of whom at least 10,000 were armed with Remington rifles.  The Khalifa received him with the utmost honour.  After a private interview, which lasted for several hours, a formal entry into the town was arranged.  At daybreak on the following morning the whole force marched into the city and camped along the northern suburbs, applauded and welcomed alike by the population and their ruler.  A few days after this a great review was held under the Kerreri hills, on the very ground where the Dervish Empire was doomed to be shattered.  But the fateful place oppressed the Khalifa with no forebodings.  He exulted in his power:  and well he might, for after the cannon had thundered indefinite salutes, no fewer than 100,000 armed men defiled to the music of the war-drums and the ombyas before the famous Black Flag.  The spectacle of the enormous numbers provoked their enthusiasm.  The triumphant Khalifa was cheered by his mighty host, who pressed upon him in their exuberant loyalty until he was almost crushed.  It was indeed a stirring scene.  The whole plain was filled with the throng.  Banners of every hue and shape waved gaily in the breeze, and the sunlight glinted from innumerable spear-points.  The swarming Dervishes displayed their bright parti-coloured jibbas.  The wild Baggara cavalry circled on the flanks of the array.  The brown dome of the Mahdi’s tomb, rising above the city, seemed to assure the warriors of supernatural aid.  Abdullah was at the summit of his power.  The movement initiated by the priest of Abba island had attained its climax.  Behind, in the plain, the frowning rocks of Surgham Hill rose ragged and gloomy, as if their silence guarded the secrets of the future.

After the feast of Bairam had been celebrated on a gigantic scale, Abu Anga was despatched to Gallabat with his army and considerable reinforcements from the troops in Omdurman, and it became evident that war with Abyssinia was imminent.  The great leader relieved the Emir Yunes, much to the latter’s disgust, of the chief command, and, since the strong Gallabat garrison was added to his own force, Abu Anga was able to take the field at the head of 15,000 riflemen and 45,000 spearmen.  The Khalifa had embarked on a great venture in planning the invasion of Abyssinia.