Massacre in the Great Temple of Tenochtitlan

In late April 1520, Cuban Governor Diego Velázquez de Cuéllar ordered conquistador Pánfilo de Narváez to arrest Hernán Cortés while Cortés was present in Tenochtitlan, capital of the Mexica (Aztec) Empire. Learning of Narváez's approach, Cortés departed the city with part of his force to confront him, leaving captain Pedro de Alvarado in command of both the Spanish contingent and oversight of the Mexica. During Cortés's absence, Mexica emperor Moctezuma sought Alvarado's permission to hold the festival of Toxcatl, a celebration honoring the deity Tezcatlipoca; Moctezuma had previously secured authorization for the festival from Cortés himself.

Alvarado came to suspect that the festival was being used as cover for a rebellion against the Spanish occupiers. After festivities began, Spanish forces sealed the exits of the temple patio and attacked the celebrants — described in Mexica accounts as including performers, spectators, and nobles — killing indiscriminately. A Mexica account, drawn from the Florentine Codex material as rendered in "Visión de los Vencidos," describes the Spanish blocking the Gate of the Eagle, the Gate of the Canestalk, and the Gate of the Snake of Mirrors before killing musicians, dancers, and onlookers with swords, including dismemberment and disembowelment, while some victims attempted to flee or hide among the dead.

Spanish accounts, including that of historian Francisco López de Gómara, offer competing explanations for the violence: some Spaniards attributed the killings to fears of a Mexica uprising tied to Narváez's arrival, others to a Mexica plan to expel the Spanish or free Moctezuma, and still others to Spanish desire to seize the gold and jewelry worn by celebrants. López de Gómara's account states that more than 600, and by some estimates over a thousand, Mexica nobles had gathered for the dance, and that Alvarado's men covered the temple entrances with soldiers before entering to kill the celebrants and take their ornaments. Despite differing explanations of motive, accounts agree that those attacked were mostly unarmed and that the killings occurred without direct provocation or warning.

The massacre deepened existing tensions between the Mexica and the Spanish, who were already holding Moctezuma captive. When Cortés returned to Tenochtitlan in late June 1520 after learning of the killings, he ordered Moctezuma to appeal for peace. Moctezuma was killed shortly afterward, though sources dispute whether Spanish captors or his own people were responsible. His brother Cuitláhuac succeeded him and supported continued resistance. The Spanish attempted to flee the city secretly during a rainstorm, but the Mexica detected the retreat and attacked, resulting in the deaths of more than 800 Spaniards and 2,000 Tlaxcalan allies, many of whom drowned in Lake Texcoco while carrying looted gold. This episode became known as La Noche Triste and was a significant event preceding the fall of the Mexica Empire in 1521.