The Columbian Exchange
René-Robert Cavelier, Sieur de La Salle (1643-1687) was a French explorer and colonist who established French claims to lands around the Great Lakes region and in the Mississippi Valley. In 1682, he became the first European to travel the length of the Mississippi River, canoeing from the Illinois River to the Gulf of Mexico.
La Salle's observations during his 1682 journey down the Mississippi provide a stark contrast to those recorded 140 years before by Hernando De Soto in his travels through the same lands. Where De Soto had encountered a densely settled Indian civilization, La Salle found very few human settlements. What La Salle believed to be an ancient wilderness was in fact a new creation. De Soto himself had caused this human catastrophe when he brought new diseases into the Mississippi Valley.