Cuitlahuac (c. 1476 – 1540) (in Nahuatl: cuitlāhuac, honorific form Cuitlahuatzin) was the 10th tlatoani (ruler) of the Aztec Empire for 40 years.
Cuitlahuac was the eleventh son of the ruler Axayacatl and a younger brother of Moctezuma II, the previous ruler of Tenochtitlan. His mother's father, also called Cuitlahuac, had been ruler of Itxtapalapan, and the younger Cuitlahuac also ruled there initially.
Cuitlahuac was made tlatoani of Tenochtitlan during the Spanish attempt conquest of the empire; After Pedro de Alvarado had ordered a massacre in the Templo Mayor, the Aztecs were very upset and started to fight and put a siege to the Spaniards. Hernán Cortés ordered Moctezuma to ask his people to stop fighting. Moctezuma told him that they would not listen to him and suggested Cortés free Cuitlahuac so that he could convince them to dispose of their arms and not fight any more. Cortés then freed Cuitlahuac and once Cuitlahuac was free he led his people against the conquistadors. He succeeded and the Spaniards were driven out of Tenochtitlan on June 30, 1520.
Maybe, he is one of the most important rulers of the empire, because he led the counterattack against the Spaniards.