Ignatius Sancho is born on a slave ship crossing the Atlantic Ocean en route from Guinea to the Spanish West Indies. At Cartanega the Bishop baptizes him and gives him the name Ignatius.
Sancho's mother dies, likely of a tropical disease, and his father commits suicide to escape slavery.
Sancho's owner takes him to England and gives him to three sisters residing in Greenwich. They give him the surname Sancho because of a presumed resemblance to Don Quixote's stout squire, the illiterate Sancho Panza. The sisters believe that ignorance of slaves provides security for their obedience but fortunately for Sancho he meets John, second duke of Montagu, who lives nearby at Blackheath. Montagu is impressed by Sancho's intelligence and encourages him to read by giving him books. The duke unsuccessfully recommends to Sancho's mistresses that they provide him with an education.
Shortly after the duke's death in 1749—seeking freedom and fearful of retribution should his mistresses discover an “amour” of his—Sancho flees from Greenwich and seeks protection from the duke's widow. She at first rejects him but soon relents and gives him a position in her household as her butler.
Upon the duchess' death in 1751 Sancho is left with an annuity of £30 and his own savings of £70.
Having squandered his money on gambling, women, and the theatre, Sancho seeks service in the household of the late duke's son-in-law George, first duke of Montagu of the new creation, who makes Sancho his valet.
Sancho marries Anne Osborne (1733–1817) in St Margaret's Church, Westminster.
Thomas Gainsborough paints Sancho's portrait at Bath.
Establishes a grocery shop at 20 Charles Street, Westminster.
As an independent male property owner (listed as a tea dealer), Sancho becomes the first known black person of African origin to vote in a British general election. He supported Lord Percy and Lord Thomas Pelham Clinton, who stood against Lord North's governing party and who won in this constituency. Overall, Lord North gained the most MPs and was re-elected Prime Minister.
Initiates correspondence with the writer Laurence Sterne, encouraging him to use his pen toward the abolition of the slave trade: “That subject, handled in your striking manner, would ease the yoke (perhaps) of many—but if only of one—Gracious God!—what a feast to a benevolent heart!”
One of Sancho's letters is reproduced in the posthumously published Letters of Laurence Sterne.
As advertised: Cottilions, Country-Dances, &c. humbly dedicated, with Permission, to the Princess-Royal, by her Royal Highness's most obedient Servant, Ignatius Sancho. To be had of the Author, at his Tea and Snuff-Shop, No. 19, Charles street, Westminster.
Sancho dies from complications associated with gout. The first black Briton to have an obituary in the papers, his obituary in the Gazetteer and New Daily Advertiser reads: “About six yesterday morning died suddenly, Mr. Ignatius Sancho, grocer, and tea-dealer, of Charles-street, Westminster, a man whose generosity and benevolence were far beyond his humble station. He was honoured with the friendship of the late Rev. Mr. Sterne, and several of the literati of these times.” He is buried three days later in St. Margaret's chapel and burying-ground, Westminster.
Motivated by “the desire of shewing that an untutored African may possess abilities equal to an European” (Letters, 4), Frances Crew edits and publishes the two-volume Letters of the Late Ignatius Sancho, an African, sold by subscription.