The Battle of Omdurman on 2 September 1898 saw General Kitchener lead an Anglo-Egyptian-Sudanese army to victory over 50,000 Mahdists in Sudan. The death of General Gordon during the siege of Khartoum 13 years before, had finally been avenged, largely thanks to ultramodern and vastly superior weapons. One year later, the British won the Mahdist War (1881 to 99), and they then ruled Sudan as a protectorate in all but name.

The Mahdist War began in Sudan in 1881 as a movement led by the inspirational Muslim leader, Muhammad Ahmad (1844 to 1885), the self-proclaimed Mahdi or Messiah of Islamic tradition. The Mahdists rejected the Ottoman-Egyptian colonial rule in Sudan with its high taxes and suppression of the lucrative slave trade. The Mahdi also wanted to spread a new form of Islam both in Sudan and elsewhere, a brand of the faith he described as "purged of heresies and accretions" (Boahen, 39). The rebellion quickly spread across several provinces of the country and easily defeated Egyptian armies sent to restore order.

Muhammad Ahmad insisted that his followers, known as ansars (or Dervishes to the British), wear the jibba, a robe of patched material which symbolised a rejection of worldly goods. When the Mahdist army went into battle, it rode its horses and camels before large red, green, and black flags inscribed with quotations from the Quran.

The Mahdists captured El Obeid in January 1883 and then defeated a large Egyptian army under the command of British Colonel William Hicks in November. These victories brought the added bonus of hundreds of modern rifles and a quantity of field guns. A Mahdist state was established in western Sudan and ot slowly expanded.

From late 1882, Egypt was taken over and run as a protectorate by the British. The British government had two objectives in this part of Africa: to control Egypt's Suez Canal and so preserve the vital sea route between Europe and British India, and to control Sudan since the Nile River runs right through that country and is vital to Egypt's welfare. However, the British Prime Minister William Gladstone was reluctant to start another expensive colonial war in Sudan, and so, instead, he chose not to send an army but the charismatic general Charles Gordon (1833 to 1885). Gordon, already a national hero after his escapades in China, was instructed to evacuate the remaining Egyptian garrisons, including at the capital Khartoum. The general ignored the order and instead decided to try to hold Khartoum until a British relief army was sent. The Mahdists besieged Khartoum from March 1884 to January 1885, and although Gladstone eventually relented and sent a relief expedition, this arrived two days too late. The Mahdists had already sacked Khartoum and killed Gordon.

The public outrage at the death of Gordon and the reluctance of the government to send him aid meant the British authorities were obliged to strike back at the Mahdists, who now controlled virtually all of Sudan except its frontier regions. However, a crisis in Afghanistan – where the Great Game of Asian imperialism was being played out between Britain and Russia – delayed British military intervention in the Sudan for over a decade.

When the decision was finally taken to address the Sudan crisis in 1896, General Horatio Herbert Kitchener (1850 to 1916) was the man selected to lead a large Anglo-Egyptian-Sudanese army and exact revenge for Gordon's death. Kitchener had extensive experience in the Middle East, had served in the Gordon relief expedition, and had defeated the Mahdists when they attacked Egypt in 1888. Kitchener was "a severe, ruthless and thorough commander who embarked upon no operation without 100 per cent preparation" (Featherstone, 9). The ambitious general, awarded the title of Sirdar (Commander) of the Egyptian Army, was certainly not liked by everyone. As the historian Laurence James notes: "Kitchener was a soldier of considerable energies, most of which were channelled into the furtherance of his career". Certainly, Kitchener was successful in rising to the very top, since he would go on to command in the Second Boer War and eventually become a field marshal, and serve as commander-in-chief in British India. Kitchener's face, with his piercing blue eyes and distinctive bristling moustache, was memorably used in recruitment posters for the First World War (1914 to 18), a time when he served as Secretary of State for War.

In the years since the fall of Khartoum, the Mahdi had died, but his state continued to flourish under his chosen successor, Khalifa 'Abdullah. The Mahdists, seeking to expand their state, had gone on to attack Egypt, Ethiopia, and the Congo Free State (the precursor to Belgian Congo) with varying degrees of success. Clearly, the Mahdist state was a threat to the stability of the entire region. It was time to assert British control in the Sudan. Another consideration was that one of Britain's great colonial rivals, France, was also interested in this area of Africa.

It was believed that by the late 1890s, the Mahdist army had grown to 50,000 or even 60,000 men. Kitchener methodically led his much smaller army of 7,500 British and 12,500 Egyptian soldiers up the Nile, accompanied by a flotilla of gunboats. Progress was slow since Kitchener insisted on building a railway, the Sudan Military Railway, as he went along to ensure his army could be easily resupplied. One member of this force, then a mere lieutenant, was Winston Churchill. There was, too, a small army of war correspondents who accompanied the expedition and sent regular reports back to Europe. Each step along the way, the army protected itself by building trenches and a thornbush fence (zariba) around the latest camp.

In June 1896, Kitchener defeated a small Mahdist force near Firket. By September 1896, Kitchener had reached Dongola, where he defeated another Mahdist force. So far, there had been no larger opposition to the expedition's leisurely progress. In July 1897, the key town of Berber was taken. By March 1898, Kitchener was finally ready to leave Berber and attack Khartoum, but first, a Mahdist army had to be faced at Atbara. Kitchener's army was equipped with the latest long-range rifles and magazine-loading Lee-Metford rifles, which no longer required the infantryman to place one bullet at a time in the chamber. Another technological development was the use of cordite bullets that produced far less smoke than before, an advantage for two reasons: a rifleman's position need not be revealed to the enemy, and a rank of riflemen did not have their view obscured after firing the first few rounds.

Kitchener's army also had the latest Maxim machine guns (which were far less liable to jamming than the older Gatling guns), and several heavy artillery pieces. With this firepower advantage, it is no real surprise that the Mahdists were defeated at the Battle of Atbara on 8 April 1898. Kitchener used his artillery to bombard the enemy camp at dawn and then swept in, using cavalry. The Mahdist army suffered 3,000 dead and 4,000 wounded. The Anglo-Egyptian army suffered 493 wounded and just 81 men killed. After regrouping and resupplying his army using his train line, Kitchener advanced to Omdurman on 1 September.

Kitchener now had around 25,000 men at his disposal as he camped near the city of Omdurman, but still by the safety of the Nile. There were infantry regiments, artillery units, horse cavalry, and the Camel Corps. Khaki uniforms had now wholly replaced the scarlet tunics of old. The pith helmet was still worn but now had a khaki cover to hide the conspicuous white underneath. The Egyptian and Sudanese soldiers also wore khaki uniforms but had a fez hat of various colours.

The Mahdist army numbered as many as 50,000 men. Thousands were equipped with older, breech-loading rifles and muskets, but the majority were armed with huge double-edged swords and spears. Although most Mahdists wore the jibba, some wore chain mail and steel helmets. This was, perhaps, one of the last great medieval-era armies seen on a battlefield.

The battle took place on the wide, featureless Kerrari plain a few miles from the city. The first stage of the battle involved Kitchener's armed steamboats bombarding Omdurman for around 50 minutes. During this bombardment, the impressive stone cupola above the tomb of the Mahdi was destroyed.

The Mahdist army came out of the city, all banners flying, horns blaring, and drums beating as they approached the invaders directly. The warriors drowned out even this noise with their shouts of La ilaha illa-llah ("There is no god but Allah"), an unsettling chorus which sounded from a distance like the rolling of waves on a pebble beach. Kitchener and his high-tech late-19th-century army waited patiently for the enemy to come within firing range. Confidence was high, especially as the rear of the camp was protected by the Nile from where the gunboats could add their artillery fire to the battle. To the right of the camp in the nearby Kerreri hills, the cavalry units awaited their chance to chase the enemy from the field. Kitchener was confident, too, but also aware that the sheer size of the enemy's army would mean that many casualties would be inevitable. The general had several barges set up to act as hospitals where the wounded could be removed from the camp to the greater safety of the river.

G. W. Steevens, a journalist with Kitchener's army, describes the first volley of fire against the charging Mahdists:

They came very fast, and they came very straight and then presently they came no farther. With a crash the bullets leaped out of the British rifles…section volleys at 2,000 yards…The British stood up in a double rank behind their zariba; the blacks lay down in their shelter-trench; both poured out death as fast as they could load and press trigger…And the enemy? No white troops would have faced that torrent of death for five minutes…You saw a rigid line gather itself up and rush on evenly; then before shrapnel shell or a Maxim the line suddenly quivered and stopped…They could never get near, and they refused to hold back. By now the ground before us was all white with dead men's drapery. Rifles grew red-hot; the soldiers seized them by the slings and dragged them back to the reserve to change for cool ones. It was not a battle, but an execution.

(Wilkinson-Latham, 34)

The British artillery fired shell after shell at the enemy in the first few minutes of the battle. British Army riflemen then joined in, and they were able to fire off 12 rounds each minute. The fate of the Mahdist infantry attack was inevitable; even groups of Mahdist cavalry were cut down before they could get anywhere near Kitchener's men. Men charging machine guns were effectively committing suicide.

Kitchener, instead of permitting further charges against his ranked men, a strategy that might well overwhelm them by sheer numbers, ordered his men to launch a counterattack. The charge of the 21st Lancers, although recklessly made without a plan and covering unknown ground that could have caused havoc with the horses, made sure the enemy did not retreat to Omdurman. The Lancers had to overcome greater numbers than expected when 3,000 Dervishes revealed themselves from within a deep trench, but the pushback was successful. Three Victoria Cross medals, Britain's highest military honour, were awarded to the Lancers. By noon, the battle was over.

At Omdurman, at least 11,000 Mahdists were killed, 6,000 were wounded, and 5,000 taken prisoner. The British-Egyptian-Sudanese total casualties numbered 291. As Kitchener understated: "I think the enemy have had a good dusting" (Asher, 401). The flower of the Sudanese nation had been wiped out. Omdurman was then entered and sacked. The Mahdi's tomb was utterly destroyed. The next day, Kitchener led a memorial service for General Gordon.

Kitchener's policy of leaving the wounded enemy unattended on the battlefield did not interfere with his replacing Gordon as the new British military national hero. The British government was rather less enamoured with Kitchener over stories of post-battle brutality, executions without trial, and the story that he had exhumed the Mahdi's bones and thrown them into the Nile (except the skull, which was converted into an inkwell). The disgrace was such that one group of MPs in the British Parliament refused to endorse the plan to pay Kitchener a cash prize for his success in the Sudanese campaign. In the end, Kitchener got his prize of £30,000 and was made a baronet; his chosen title was Kitchener of Khartoum. Kitchener did make a donation to the new Gordon Memorial College in Khartoum.

Khalifa 'Abdullah was not captured at Omdurman, though, and, with his 10,000 remaining followers, he continued the rebellion from the province of Kordofan. The Mahdist War finally came to an end in November 1899 when Khalīfa 'Abdullah's army was defeated at the Battle of Umm Diwaykarat (aka Um Debreikat).

After seeing off a rival French expeditionary force at Fashoda (an episode known as the Fashoda Incident, which nearly started a war between the two colonial powers), Kitchener was made Military Governor of all of Sudan. A modern administrative government was established, and Sudan was ruled as a British protectorate in all but name. Sudan did not gain independence until 1956. The Battle of Omdurman is the climax of Zoltan Korda's 1939 film The Four Feathers and its various remakes.