The first African prose writer whose work was published in England - his Letters appeared in 1782, two years after his death, and was an immediate best-seller - was born in 1729 on a slave ship in the mid-Atlantic. At Cartagena, on the coast of Columbia, he was christened Ignatius. His mother died soon afterwards, and his father killed himself rather than exist as a slave. When Ignatius was about two, his owner brought him to England and gave him to three maiden sisters who lived in Greenwich. These ladies called him Sancho because they thought he looked like Don Quixote's squire. They did not believe in the education of slaves; nonetheless, Ignatius taught himself to read and write.

The Duke of Montagu, who lived in nearby Blackheath, liked the young man's acquisitive nature and bought him books, and tried to persuade the sisters to educate him, but they would not, So Ignatius ran away, and stayed with the Montagus. The duchess engaged him as a butler, and he was able to indulge in his passion for reading and subsequently wrote poetry, two stage plays and a Theory of Music dedicated to the Princess Royal. He was also a composer, with three collections of songs, minuets, and other pieces for violin, mandolin, flute and harpsichord all published anonymously. He loved the theatre and would regularly go to Drury Lane to see the great actor Garrick, who later became a friend
Sancho was embraced by London's literary and artistic set.

Gainsborough painted his portrait in 1768. He also became friends with the historical painter John Hamilton Mortimer, and the writers Samuel Johnson and Laurence Sterne. Sancho left the service of the Montagus in 1773, and with a legacy left to him by the Duchess of Montagu, he opened a grocery shop in Charles Street, Westminster with his wife Anne. He died in 1780, and two years later his Letters were published, proving that 'an untutored African may possess abilities equal to a European'. His work attracted over 1,200 subscribers. 'Let it no longer be said', wrote one reviewer, 'by half informed philosophers, and superficial investigators of human nature, that Negers, as they are vulgarly called, are inferior to any white nation in mental abilities'.