Moctezuma II or Montezuma II (1466-1520) was an Aztec emperor, c. 1502-1520. He is sometimes referred to as Moctezuma only. The use of a regnal number is only for modern distinction from the "other" Moctezuma, referred to as Moctezuma I. Montezuma is an older English spelling of the name now spelled Moctezuma. Another way to distinguish them besides using Roman numerals is that Moctezuma I was Moctezuma Ilhuicamina and Moctezuma II was Moctezuma Xocoyotzin. The first means "lone who shoots an arrow into the sky". Xocoyotzin simply means "the youngest".

Moctezuma II, heir of Auitzotl, was the ruler of the city of Tenochtitlán who increased its power to utterly dominate its sister cities of Texcoco and Tlatelolco. Legend has it that there were eight signs in the ten years prior to the arrival of the Spanish conquistadors, signalling the collapse of the Aztec empire. These were:

  1. A pillar of fire appeared in the night sky (possibly a comet?);
  2. A comet appeared in the sky during the day.
  3. The temple of Huitzilopochtli was destroyed by fire;
  4. A bolt of lightning struck the Tzonmolco temple.
  5. Tenochtitlan was flooded;
  6. Strange people with many heads but one body were seen walking through that city;
  7. A woman was heard weeping a dirge for the Aztecs;
  8. A strange bird was caught. When Moctezuma looked into its mirror-like eyes, he saw unfamilar men landing on the coast.

In the spring of 1519, he received the first reports of aliens landing on the east coast of his empire. On November 8, 1519, he met Hernán Cortés, whom he believed to be the god Quetzalcoatl.

During Cortés's absence, the deputy governor decreed that the Aztec ritual of human sacrifice must stop. The people rose up in revolt, and the Spanish seized Moctezuma as a captive. On July 1, 1520, in an effort to assuage the raging mob, Moctezuma appeared on the balcony of his palace, appealing to his countrymen to retreat. The people were appalled by their emperor's complicity with the Spanish and pelted him with rocks and darts. He died a short time after the attack. Moctezuma was then succeeded by Cuitlahuac and Cuauhtémoc. By the following year, the Aztec empire had entirely succumbed to the Spanish.