In 1856, Zulu prince Mbuyasi, outnumbered by his brother Cetshwayo's forces, had requested help from Walmsley, which was refused. Dunn was sent instead to negotiate peace terms between the two warring Zulu brothers, which failed. With a small force of Native Police, Dunn supported the Zulu king
Mpande's son Mbuyasi in the bloody battle of succession fought between him and the king's oldest son
Cetshwayo. On 2 December 1856, at the
Battle of Ndondakusuka, Mbuyazi's forces lost and he was killed, forcing Dunn and other white settlers to flee back to Natal. After the battle, Cetshwayo then clashed with two English traders and took 1,000 head of cattle. His involvement in the battle led to resentment towards Dunn by the white settlers of Natal, so on his own account he re-crossed the Tugela to ask the winner, Cetshwayo, to return the cattle that had belonged to the traders. Cetshwayo agreed, and requested that Dunn become his advisor in matters related to the
British. The cattle were returned. He resigned his position in Natal and settled in Zululand in June/July 1857 and was allocated land on the coast of southern Zululand at
oNgoya. With use of his land, Zulu marriages and the loaning of cattle, Dunn built a network of clients and contacts along the Zululand coast that allowed him to exploit the region's wealth. During the 1860s, he was involved in the trade of firearms into Zululand with the exchange of cattle for rifles via
Lourenço Marques along the Zululand coast, as well as the flow of
Tsonga workers to Natal for the agricultural industry, from the former. He would later be appointed as Protector of Immigrants for Zululand in 1874 by
Theophilus Shepstone. Another important business income for Dunn was hunting. Organising his Zulu subjects as hunters, guides and porters, they successfully hunted for ivory, hides and skins, but by 1880, game had become scarce in Zululand. On 18 October 1872, King Mpande died at the age of 74 and Cetshwayo became king. Dunn's power and influence rose; he handled nearly all of Cetshwayo's foreign correspondence. Though
Mpande and Cetshwayo had successfully resisted attempts by the
Boers and the British to encroach on their territory, the
Anglo-Zulu War of 1879 forced John Dunn to pick sides, and he sided with the British. ==Anglo-Zulu War and its aftermath==