The Aztecs believed in polytheism. Quetzalcoatl (feathered snake), Huitzilopochtli (hummingbird of the south) and Tezcatlipoca (smoking mirror) were the most important Gods. Sometimes the Aztecs killed humans to please their gods. Between 1519 and 1521 the Spanish leader Hernán Cortés defeated the Aztecs and took their empire. Some Aztecs did not want to fight against the soldiers of Cortés, because they thought they were Gods.