Hernando de Soto

On June 3, 1539, Hernando de Soto claimed Florida for Spain. Exactly one year later, he and his men became the first Europeans to cross the Appalachian Mountains. From the article:

"De Soto set out from Spain in April 1538, set with 10 ships and 700 men. After a stop in Cuba, the expedition landed at Tampa Bay in May 1539. They moved inland and eventually set up camp for the winter at a small Indian village near present-day Tallahassee. In the spring, De Soto led his men north, through Georgia, and west, through the Carolinas and Tennessee, guided by Indians whom they took captive along the way. With no success finding the gold they sought, the Spaniards headed back south into Alabama towards Mobile Bay, seeking to rendezvous with their ships, when they were attacked by an Indian contingent near present-day Mobile in October 1540. In the bloody battle that followed, the Spaniards killed hundreds of Indians and suffered severe casualties themselves."