In the 1500s, Spanish explorer Juan Ponce de Leon landed in Florida and explored the Gulf Coast of the United States. In 1519, Spanish conquistador Hernán Cortés landed in Mexico and began the conquest of the Aztec Empire. In 1540, Spanish explorer Francisco Vásquez de Coronado led a large expedition into the American Southwest. In 1541, Spanish explorer Hernando de Soto crossed the Mississippi River and explored the southeastern United States.