The Spanish conquest of the Aztec Empire was one of the most significant events in the Spanish colonization of the Americas. The campaign began in February 1519, and was declared victorious on August 13, 1521, when a coalition army of Spanish forces and native Tlaxcalan warriors led by Hernán Cortés and Xicotencatl the Younger captured Tenochtitlan, the capital of the Aztec Empire. Moctezuma was convinced that Hernan Cortes was a god, as the Spanish brought horses and guns, which the Aztecs had never seen before.

During the campaign, Cortés was offered support from a number of tributaries and rivals of the Aztecs, including the Totonacs, and the Tlaxcaltecas. In their advance, the allies were tricked and ambushed several times by the peoples they encountered. After eight months of battles and negotiations, which overcame the diplomatic resistance of the Aztec Emperor Moctezuma II to his visit, Cortés arrived in Tenochtitlan on November 8, 1519, where he took up residence welcomed by Moctezuma. When news reached Cortés of the death of several of his men during the Aztec attack on the Totonacs in Veracruz, he took Moctezuma captive in his own palace and ruled through him for months. After the massacre at the Main Temple of Tenochtitlan and a rebellion by the population of the city, Cortés and his men had to fight their way out of the capital city during the Noche Triste in June, 1520. However, the Spanish and Tlaxcalans would return with reinforcements and a siege that led to the fall of Tenochtitlan a year later.