Robert Cavelier La Salle Sieur de

La Salle, Robert Cavelier, Sieur de (1643–87), French explorer and fur trader in North America who claimed the Louisiana territory for France. In Canada from 1666, he commanded Fort Frontenac, sailed across Lake Michigan (1679), explored the Illinois River, and followed the Mississippi River to its mouth on the Gulf of Mexico. In 1684, sailing to plant a colony there, his fleet was wrecked by storms and Spanish raiders. He was killed by a mutinous crew.