In 1682, one hundred and forty years after Hernando de Soto and his conquistadors searched for treasure west of the Mississippi River, the French explorer LaSalle claimed all the land, resources, and peoples of the country of Louisiana in the name of King Louis XIV of France. In the years that followed, trading centers such as St. Louis, Natchez, and New Orleans developed as the Mississippi carried skins, pelts, bear oil, and other frontier products to market, and by 1721 eight thousand people crowded the French colonies while rivalries grew between the French and increasing numbers of English traders. In 1762 France ceded the entire territory to Spain in payment for aid during the French-Indian War, and Spain, fearing growing American influence, tried to protect the territory by controlling river trade, but the controls failed. In July 1800 Napoleon opened negotiations with Spain for Louisiana's return to France, and a temporary treaty stipulated that France would not sell or otherwise dispose of the territory to any third party, leading Spain to believe its interests were safe from American control. Lands along the Mississippi often proved unsuitable for settlement but provided an excellent environment for wildlife, especially fur-bearing mammals, and French traders quickly built a trade network with Indians along the river and its tributaries. Fur markets in Europe encouraged early Anglo-Americans in the area, and among the animals that fed early explorers and clothed Europeans were beaver, mink, raccoon, swamp rabbits, opossum, gray squirrels, and occasional deer, many of which still live year-round in the remaining wetlands of eastern Arkansas.