Cortes wanted to entirely understand the cause of the Indians' rebellion. He interrogated them [the Spaniards] altogether. Some said it was caused by the message sent by Narvaez, others because the people wanted to toss the Spaniards out of Mexico [Tenochtitlan], which had been planned as soon as the ships had arrived, because while they were fighting they shouted "Get out!" at them. Others said it was to liberate Montezuma, for they fought saying, "Free our god and King if you don't want to die!" Still others said it was to steal the gold, silver, and jewels that the Spaniards had, because they heard the Indians say, "Here you shall leave the gold that you have taken!" Again, some said it was to keep the Tlaxcalans and other mortal enemies out of Mexico. Finally, many believed that taking their idols as gods, they had given themselves to the devil.
Any of these things would have been enough to cause the rebellion, not to mention all of them together. But the principal one was that a few days after Cortes left to confront Narvaez, it became time for a festival the Mexicas wanted to celebrate in their traditional way. . . . They begged Pedro de Alvarado to give them his permission, so [the Spaniards] wouldn't think that they planned to kill them. Alvarado consented provided that there were no sacrifices, no people killed, and no one had weapons.
More than 600 gentlemen and several lords gathered in the yard of the largest temple; some said there were more than a thousand there. They made a lot of noise with their drums, shells, bugles, and hendidos, which sounded like a loud whistle. Preparing their festival, they were naked, but covered with precious stones, pearls, necklaces, belts, bracelets, many jewels of gold, silver, and mother-of-pearl, wearing very rich feathers on their heads. They performed a dance called the mazeualiztli, which is called that because it is a holiday from work [symbolized by the word for farmer, macehaulli]. . . . They laid mats in the patio of the temple and played drums on them. They danced in circles, holding hands, to the music of the singers, to which they responded.
The songs were sacred, and not profane, and were sung to praise the god honored in the festival, to induce him to provide water and grain, health, and victory, or to thank him for healthy children and other things. And those who knew the language and these ceremonial rites said that when the people danced in the temples, they perform very different from those who danced the netoteliztli, in voice, movement of the body, head, arms, and feet, by which they manifested their concepts of good and evil. The Spaniards called this dance, an areito, a word they brought from the islands of Cuba and Santo Domingo.
While the Mexica gentlemen were dancing in the temple yard of Vitcilopuchtli [Huitzilopochtli], Pedro de Alvarado went there. Whether on [the basis of] his own opinion or in an agreement decided by everyone, I don't know, but some say he had been warned that the Indian nobles of the city had assembled to plot the mutiny and the rebellion, which they later carried out; others, believe that [the Spaniards] went to watch them perform this famous and praised dance, and seeing how rich they were and wanting the gold the Indians were wearing, he [Alvarado] covered each of the entrances with ten or twelve Spaniards and went inside with more than fifty [Spaniards], and without remorse and lacking any Christian piety, they brutally stabbed and killed the Indians, and took what they were wearing.