Radisson, Pierre Esprit, << ra dee SAWN, pyair ehs PREE >> (1640?-1710), was a French explorer and fur trader. He and his brother-in-law, Médard Chouart, Sieur des Groseilliers, were among the first white people to explore the areas around and south of Lake Superior.
Born in France, Radisson moved to what is now Canada as a boy. Mohawk warriors captured him around 1651, but he escaped about two years later. Radisson and Groseilliers explored the Lake Superior area in 1659-1660. After quarreling with the French over fur-trading rights, the pair went to England in 1665. They persuaded some English merchants to fund a trading expedition to Hudson Bay. This trip led to the creation of the Hudson’s Bay Company, an English fur-trading firm, in 1670. Radisson and Groseilliers worked for the firm from 1670 to 1675, then went to France. About 1682-1683, Radisson returned to Hudson Bay as a supporter of French interests in the region. But in 1684, he transferred his loyalty to the English. Radisson lived in London from 1687 until his death.