The Zulu and the Boers had had their differences since 1854 when Boers settled in areas they later called Republic of Utrecht near the border of Zulu area. 1865 Boer troops under Paul Kruger and Cetewayo's warriors almost came to blows over the possession of area north of the Pongolo. Negotiations were not particularly successful, especially because Boers did not see Africans as their equals.
When the British Empire annexed Transvaal in 1877, they inherited the problem. Natal secretary for Native Affairs, Theophilus Shepstone, initially defended the Zulu against the Boers. He soon reversed the decision after the annexation to keep the Boers content.
In 1878 Sir Henry Bartle Frere, British Commissioner for South Africa, used a minor border incursion – two warriors had fetched two eloped girls from Natal – as a pretext to demand 500 head of cattle from the Zulu as reparations. Cetewayo only sent £50 worth of gold. When two surveyors were captured in Zululand, Frere demanded more reparations and Cetewayo again refused. Frere sent emissaries to meet him and tell his demands. One of them was that Cetewayo should disband his 40.000-strong impi army in 20 days.
Frere was either very arrogant or wanted to deliberately insult Cetewayo. If so, he succeeded. Cetewayo rejected the demands on December 11.
In January 11 1879 British troops under the command of Lieutenant general Frederic Augustus Thesiger, Second Lord Chelmsford invaded Zululand. The first troops crossed the border on January 6. He had 4700 men of which 1857 of were European British soldiers. The rest were Basuto cavalrymen, Kaffirs and members of the paramilitary Natal Native Contingent.
On January 22 Chelmford's forces were overrun in Isandlhwana. Zulu impis armed with muskets, short spears and leather shields defeated a British Infantry column with Native(mostly from Natal) and light cavalry support. 1329 British, Indian and Basuto troops were killed. Approximately 50 British soldiers escaped.
Hours after the battle 4000 Zulu warriors of 4 impi attacked a border post of Rorke's Drift which had only 139 men, 30 of them walking sick. Most of the Natal Native Contingent had fled before the attack – only few stayed. The British drove the attackers away after ten hours of night combat, suffering 17 dead and 15 wounded. Zulus lost maybe 500-600 men. Afterwards 11 British soldiers were awarded the Victoria Cross.
The Zulu troops also isolated Colonel Pearson's right-flank column from the border and his men were besieged for three months at Eshowe, a deserted mission station.
Chelmford had lost his center column and his plans were in tatters. However, Zulu victory in Isandlhwana had been gained with heavy casualties and Cetewayo could not mount a counter-offensive. Chelmford regrouped and called for reinforcements when his troops kept raiding over Zulu border. He had been relieved of his post back in Britain and his successor Sir Garnet Wolseley was enroute. The British sent for troops from all over the empire to Cape Town. By the end of March 29 Chelmford could mount an offensive of 8500 men (including men from the Royal Navy and 91st Highlanders) from Fort Tenedos to relieve Eshowe.
By that time Zulus had already ambushed a convoy in March 12 in Intombi River. Only 12 of 120 men escaped.
Chelmford told Sir Evelyn Wood's troops (Staffordshire Volunteers and Boers, 675 men in total) to attack the Zulu stronghold in Hlobane. Lieutenant colonel Redverds Buller, later Second Boer War commander, lead the attack in March 28. However, The Zulu main army (26.000 men) arrived to help their besieged tribesmen and the British troops scattered. The next day 25.000 warriors attacked Wood's camp (2068 men) in Khambula (apparently without Ceteway's permission) . The British drove them off after five hours of heavy fighting. British losses amounted to 29 the Zulus lost approximately 2000. It turned out to be a decisive battle.
In April 2-3 Chelmsford's forces broke through Zulu lines in kwaGingindlovu and relieved Pearson's men. They evacuated Eshowe at April 5 after which Zulu burned it down.
Chelmford regrouped again and attacked Zululand in June. The new start was not promising. British troops were ambushed in June 1. One of the British casualties was the exiled heir to the French throne, Napoleon Eugene Bonaparte, who had volunteered to serve in the British army.
British troops advanced slowly towards Ulundi and reached it at the end of June. On July 4 Chelmsford's 4166 white and 1005 black soldiers, aided by artillery and Gatling guns, defeated a Zulu force of up to 20000, took over Ulundi and burned it down, including the royal enclosure. The Zulu lost 1500, and the British lost 13 men. Cetewayo fled. Chelmsford resigned when his successor arrived a few days later.
The British took weeks to quell the rest of the resistance. Eventually they captured Cetewayo on August 28, announced his abdication and exiled him to London. The war ended September 1. The British divided Zululand among 13 different chiefs and settlers - which lead to intra-tribal squabbles and civil war...
Sir Frere was relegated to a minor post in Cape Town.