T-shirt, Mr Gates is as much a character in the television films as the characters he discusses: King Solomon or Don Francisco de Souza, Ivory Coast's most notorious slave trader.

ECONOMIST: Mary Poppins is a black man

Steve Turner's book Amazing Grace: The Story of America's Most Beloved Song tells the story of composer John Newton's conversion from slave trader to abolitionist, and traces the evolution of the song from its composition in 1772 as a hymn with no set tune to the version familiar today.

NPR: 'Amazing Grace'

However, he later discovered that this was the name of a Kanuri slave-trader who captured and sold his kinsmen.

BBC: Black Britons find their African roots

Imoinda, however, prefers execution to submission, but is sold to a white slave-trader instead by a character not in the original, the king's wicked minister, Orumba.

ECONOMIST: Theatre at Stratford