A great explorer in North America, recognized for the discovery of the mouths of the Mississippi River, René-Robert Cavelier de La Salle obtained a fief, in 1667, from the Séminaire de Saint-Sulpice de Montréal, seignieur of the island of Montréal. The boundaries of the fief corresponded, more or less, to the present-day territory of the Borough of LaSalle, which Cavelier de La Salle called Coste Saint-Sulpice.
The impetuous nature of this well-known historical figure and his desire to discover new territories prompted him, in 1669, to sell his fief to the Séminaire de Saint-Sulpice, and his estate, to Jean Milot, an edge-tool maker from Rivière Saint-Pierre. Cavelier de La Salle then began his voyages, which would lead him to explore part of the Ohio River, part of the Great Lakes and their region and then the Mississippi, up to the Gulf of Mexico, after being given the responsibility of discovering the mouth and the Mexican coast.
