Chief Nanna Olomu (c.1840–1916) of Ebrohimi was the wealthiest and most powerful Itsekiri trader of the late nineteenth-century Benin River, holding the British-recognised office of Governor of the River (1884–1894). When the Royal Navy under Admiral Sir Frederick Bedford bombarded and destroyed Ebrohimi in September 1894, Nanna escaped to Lagos, surrendered, was tried at Old Calabar and deported to the Gold Coast (Accra) on charges related to monopolising the palm-oil trade and refusing to open Itsekiri markets to British firms. The deeper context was monetary: Nanna's working capital was denominated in cowries and manillas, currencies the British had already crashed by flooding the coast with Zanzibar ring cowries from the 1840s — see How the currency fell before the flag. Ebrohimi was the western-Delta holdout of an indigenous monetary regime Britain was determined to replace with sterling.
George William Neville (1852–1932), born in Richmond near London, was the West African agent of Elder Dempster & Co. of Liverpool, an unofficial member of the Lagos Legislative Council, and in 1891 a co-founder — with Sir Alfred Lewis Jones — of the Bank of British West Africa (the institution that would become First Bank of Nigeria). Long before Nanna's trial Neville had publicly defended African rulers against what he called the high-handedness of British consuls, writing of Consul Phillips's treatment of Oba Ovonramwen: "I contend that we have no more right to ride roughshod over the susceptibilities of subject races than we have to storm the tabernacles and tear down the banners of the Salvation Army."
Neville and Nanna were close personal friends and trading partners. Neville served as a character witness at Nanna's trial and gave the first authoritative European description of Nanna's military strength — "Nanna owns 100 war canoes, separately from 236 large trade canoes, and 20,000 war boys." Through the years of exile Neville petitioned the Colonial Office, arguing that the Nanna he knew was incapable of the crimes laid against him. The campaign succeeded: Nanna was officially informed of his release and sailed from Accra on 6 August 1906. He arrived back at Koko in the Benin River two days later.
In gratitude Nanna named one of his sons after Neville and, on 20 July 1906, wrote to him from Accra: "I am unable to describe my feelings to you and your friends for your kindness towards me and the whole of my relations and friends in bringing my matter to such termination after so many years passed in exile… so long as I am in this world, I hope I shall never forgetting [you] and others." Nanna dedicated his return to his English friend.
Every year since, the Itsekiri community of Koko in Warri North Local Government Area of Delta State has kept 8 August as Neville's Day — a homecoming feast honouring the British merchant-banker who fought for an African chief's freedom. Nanna died in 1916; Neville in 1929; the friendship is now in its second century of commemoration.