In 1660, the Company of Royal Adventurers Trading to Africa was established under the leadership of Charles II's brother James, the Duke of York. Founded as a slaving company, the Royal African Company, as it became known, also traded in gold. African gold was mined in the interior before being brought to the Company's trading posts, or slave forts, on the Gulf of Guinea, also known as the Gold Coast. This gold was supplied to the English mint, thus the name guinea for an old English gold coin. The African origins of this precious metal are also revealed by the presence of the Company's frank, an elephant, stamped on the coins.

A century later, in 1788, the African Association was founded in London with the twin goals of discovering the source of the River Niger and locating the city of Timbuktu. Rumours that there were cities of gold somewhere in the heart of the Sahara had been circulating for centuries, fed by the seemingly inexhaustible supplies coming to the African coast. For reasons of general ignorance and missed trading...