Muhammad Ahmad bin Abd Allah  (12 August 1845 – 22 June 1885) was a religious leader of the Sufi Samaniyya order in Sudan. On 29 June 1881, he proclaimed himself as the Mahdi or messianic redeemer of the Islamic faith.

His proclamation came during a period of widespread resentment among the Arabic part of the Sudanese population. They resented the oppressive policies of their Turco-Egyptian rulers (who were also muslims).

There were messianic beliefs among the various Sudanese religious sects of the time. There were earlier Mahdist movements in West Africa, and Wahhabism and other puritanical forms of Islamic revivalism. The root cause of this was the growing military and economic dominance of the European powers throughout the 19th century.

The British influenced the Sudan, and had claimed it as a "Joint Anglo-Egyptian Condominion". In general, the British were behind the rule of the Khedives of the Muhammad Ali Pasha dynasty in Egypt. At the time of the Mahdi, Egypt and the Sudan were ruled jointly by Tewfik Pasha as recognised by the Ottoman Empire, and by the British. Britain's claim to the Sudan led to British forces being sent there after the Mahdi had beaten the forces of the Khedive. The British government appointed General Charles George Gordon ("Gordon pasha") to be Governor General of the Sudan, and that led to his famous death in Khartoum at the hands of the Mahdi's forces.

From his announcement of the Mahdiyya in June 1881 until the fall of Khartoum in January 1885, Muhammad Ahmad led a successful military campaign against the Turco-Egyptian government of the Sudan. The fighting ended with the death of Gordon in Khartoum. After Muhammad Ahmad's unexpected death on 22 June 1885, only six months after the conquest of Khartoum, his chief deputy took over the administration of the Sudan. Churchill says they had by then killed all the people capable of running the country.

Aftermath 
The rule of Sudan by the Mahdists turned out badly for its people. Sudan's economy was all but destroyed, and the population had declined by about one-half because of famine, disease, persecution, and warfare. Millions died in the Sudan from the start of the Mahdist state to its fall. None of the country's traditional institutions or loyalties remained intact. Tribes had been divided in their attitudes toward Mahdism, religious brotherhoods had been weakened, and orthodox religious leaders had vanished.

Reconquest of the Sudan 
In 1895, the British Government authorized Herbert Kitchener to launch a campaign to reconquer the Sudan. Britain provided men and matériel, while Egypt financed the expedition. The Anglo-Egyptian Nile Expeditionary Force included 25,800 men, 8,600 of whom were British. The remainder were troops belonging to Egyptian units, including six battalions recruited in southern Sudan.

An armed river flotilla escorted the force, which also had artillery support. In preparation for the attack, the British established army headquarters at Wadi Halfa. In March 1896, the campaign started. In September, Kitchener captured Dunqulah. The British then constructed a rail line from Wadi Halfa to Abu Hamad and an extension parallel to the Nile to transport troops and supplies to Berber. Anglo-Egyptian units fought and won various smaller engagements. Eventually, Kitchener's soldiers marched and sailed toward Omdurman.

In Omdurman, on 2 September 1898, the Sudanese leader, now known as the Khalifa, committed his 52,000-man army to a frontal assault against the Anglo-Egyptian force, which was massed on the plain outside the town. The outcome never was in doubt, largely because of superior British firepower. During the five-hour battle, about 11,000 Mahdists died, whereas Anglo-Egyptian losses amounted to 48 dead and fewer than 400 wounded.
 
Mopping-up operations took several years, but organized resistance ended when the Khalifa, who had escaped to Kurdufan, died fighting in battle at Umm Diwaykarat, November 1899. Many areas welcomed the downfall of his regime.

Churchill, Winston 1889. The River War: an historical account of the reconquest of the Soudan. 2 vols, London: Longmans Green. Churchill was on Kitchener's expedition as a newspaper reporter. His book was abridged (shortened), and republished in 1902 as a single volume.

References 

Sudan
Religious leaders
1845 births
1885 deaths
Muslims