Pierre-Esprit Radisson - Wikipedia. Pierre-Esprit Radisson (1636/1640–1710) was a French fur trader and explorer in New France.He is often linked to his brother-in-law Médard des Groseilliers.The decision of Radisson and Groseilliers to enter the English service led to the formation of the Hudson's Bay Company.His career was particularly notable for its repeated transitions between serving ...