On May 8, 1541, south of present-day Memphis, Tennessee, Spanish conquistador Hernando de Soto reaches the Mississippi River, one of the first European explorers to ever do so. After building flatboats, de Soto and his 400 ragged troops crossed the great river under the cover of night, in order to avoid the armed Native Americans who patrolled the river daily in war canoes. From there the conquistadors headed into present-day Arkansas, continuing their fruitless two-year-old search for gold and silver in the American wilderness.

Born in the last years of the 15th century, de Soto first came to the New World in 1514. By then, the Spanish had established bases in the Caribbean and on the coasts of the American mainland. A fine horseman and a daring adventurer, de Soto explored Central America and accumulated considerable wealth through the slave trade. In 1532, he joined Francisco Pizarro in the conquest of Peru. Pizarro, de Soto, and 167 other Spaniards succeeding in conquering the Inca empire, and de Soto became a rich man. He returned to Spain in 1536 but soon grew restless and jealous of Pizarro and Hernando Cortes, whose fame as conquistadors overshadowed his own. Holy Roman Emperor Charles V responded by making de Soto governor of Cuba with a right to conquer Florida, and thus the North American mainland.

In late May 1539, de Soto landed on the west coast of Florida with 600 troops, servants, and staff, 200 horses, and a pack of bloodhounds. From there, the army set about subduing the natives, seizing any valuables they stumbled upon, and preparing the region for eventual Spanish colonization. Traveling through Florida, Georgia, South Carolina, across the Appalachians, and back to Alabama, de Soto failed to find the gold and silver he desired, but he did seize a valuable collection of pearls at Cofitachequi, in present-day Georgia. Decisive conquest eluded the Spaniards, as what would become the United States lacked the large, centralized civilizations of Mexico and Peru.

As was the method of Spanish conquest elsewhere in the Americas, de Soto ill-treated and enslaved the natives he encountered. For the most part, the Native warriors they met were intimidated by the Spanish horsemen and kept their distance. In October 1540, however, the tables were turned when a confederation of Native Americans attacked the Spaniards at the fortified town of Mabila, near present-day Mobile, Alabama. All the Native Americans were killed along with 20 of de Soto’s men. Several hundred Spaniards were wounded. In addition, the conscripts they had come to depend on to bear their supplies fled with the baggage.

De Soto could have marched south to reconvene with his ships along the Gulf Coast, but instead he ordered his expedition northwest in search of America’s elusive riches. In May 1541, the army reached and crossed the Mississippi River, probably the first Europeans ever to do so. From there, they traveled through present-day Arkansas and Louisiana, still with few material gains to show for their efforts. Turning back to the Mississippi, de Soto died of a fever on its banks on May 21, 1542. In order that local tribes would not learn of his death, and thus disprove de Soto’s claims of divinity, his men buried his body in the Mississippi River.

The Spaniards, now under the command of Luis de Moscoso, traveled west again, crossing into north Texas before returning to the Mississippi. With nearly half of the original expedition dead, the Spaniards built rafts and traveled down the river to the sea, and then made their way down the Texas coast to New Spain, finally reaching Veracruz, Mexico, in late 1543.