Born 1740
Died 1791, West Africa

In the late eighteenth century, the West knew little about the interior of Africa, although Europeans had trading settlements along the African coast. In 1788, a group of twelve London gentlemen, led by scientist and explorer Sir Joseph Banks (1743–1820), formed the Association for Promoting the Discovery of the Interior Parts of Africa—also known as the African Association. The group was especially interested in sending explorers to Africa’s Niger River region. They had heard rumors about the area’s great wealth and of a rich trade center there, the city of Timbuktu.

In 1788, the African Association assigned two men to explore the Niger River. It was a challenging mission, because no Westerner had actually seen the river, and nothing was known about where it originated, in which direction it flowed, or if it emptied into the sea. Simon...