Hernán Cortés was a Spanish conquistador known for leading the expedition that resulted in the fall of the Aztec Empire in the early 16th century. Born in 1485 in Medellín, Spain, he sailed to the New World in 1504 and became involved in various expeditions in Hispaniola and Cuba before his famous journey to Mexico. Cortés arrived in Mexico in 1519, where he encountered the Aztec ruler Moctezuma II. Through a combination of military strategy, alliances with local tribes, and the spread of diseases like smallpox, he captured Tenochtitlán, the Aztec capital, in 1521, leading to significant changes in the region's history.