Hernán Cortés was a conquistador (Spanish for conqueror) who caused the fall of Tenochtitlán. Since Tenochtitlán was the capital, the rest of the Aztec Empire fell as well.
When Cortés came to Tenochtitlán, he was welcomed by the Aztec leader, Moctezuma II. Cortés then took Moctezuma hostage in his own home and used him as a puppet to control the Empire from behind the scenes. Eventually, the Aztecs distrusted Moctezuma and killed him, leading to the fall of the capital and the empire.
