June 30, 1520: Faced with an Aztec revolt against their rule, forces under the Spanish conquistador Hernán Cortés fight their way out of Tenochtitlan at a heavy cost. Known to the Spanish as La Noche Triste, or “the Night of Sadness,” many soldiers drowned in Lake Texcoco when the vessel carrying them and Aztec treasures hoarded by Cortés sank. Montezuma II, the Aztec emperor who had become merely a subject of Cortés in the previous year, was also killed during the struggle; by the Aztecs or the Spanish, it is not known.
Tenochtitlan was founded in 1325 A.D. by a wandering tribe of hunters and gatherers on islands in Lake Texcoco, near the present site of Mexico City. In only one century, this civilization grew into the Aztec Empire, due largely to its advanced system of agriculture. The empire came to dominate central Mexico and by the ascendance of Montezuma II in 1502 had reached its greatest extent, reaching as far south as perhaps modern-day Nicaragua. At the time, the empire was held together primarily by Aztec military strength, and Montezuma II set about establishing a bureaucracy, creating provinces that would pay tribute to the imperial capital of Tenochtitlan. The conquered peoples resented the Aztec demands for tribute and victims for the religious sacrifices, but the Aztec military kept rebellion at bay.
At Veracruz, Cortés trained his army and then burned his ships to ensure loyalty to his plans for conquest. Having learned of political strife in the Aztec Empire, Cortés led his force into the Mexican interior. On the way to Tenochtitlan, he clashed with locals, but many of these peoples, including the nation of Tlaxcala, became his allies after learning of his plan to conquer their hated Aztec rulers. Hearing of the approach of Cortes, with his frightful horses and sophisticated weapons, Montezuma II tried to buy him off, but Cortes would not be dissuaded. On November 8, 1519, the Spaniards and their 1,000 Tlaxcaltec warriors were allowed to enter Tenochtitlan unopposed.