From Díaz del Castillo, Vol. 2, Chapter 83

[After telling the Cholulans that they should abandon their Idols, end human sacrifice, and stop practicing sodomy, all of which offended Christians, Cortés asked them through Doña Marina]: To what purpose had they quite recently prepared many long and strong poles with collars and cords and placed them in a house near to the Great Temple? Why for the last three days had they been building barricades and digging holes in the streets and fortifying rooftops? Why had they removed their children and wives and property from the city? [He told them that] Their ill will, however, had been plainly shown, and they had not been able to hide their treason, they had not even given us food to eat, and as a mockery had brought us firewood and water, and said that there was no corn. Cortés added that he knew there were many companies of warriors cached in ravines near by the city to carry out their treacherous plans, thinking that we will take that road to Mexico [Tenochtitlan] and hoping that with the help of those with us to trap us, this night even, to execute their treacherous plans. So in return for our having come as brothers to tell them what Our Lord God and the King have ordained, they wished to kill us and eat our flesh, and had already prepared the pots with salt and peppers and tomatoes. If this were what they wanted, it would have been better for them to make war on us in the open field like good and valiant warriors, as did their neighbors the Tlaxcalans.

Cortés then told them he was certain all had been planned in the city and that they had even promised their Idol, the patron of warfare, that twenty of us should be sacrificed before it, that three nights ago they had sacrificed seven Indians to obtain victory, which was promised them; but as [the Idol] was both evil and false, it neither had, nor would have power against us, and all these evil and traitorous designs which they had planned and put into effect were about to recoil on themselves. That was the speech that Doña Marina translated for them.

The priests, Caciques, and captains understood it perfectly, said it was true but that they were not to blame for it, for they were following the orders transmitted by the ambassadors of their master, Moctezuma.

Then Cortés cried out, "Royal laws command that treason cannot remain unpunished; for your crime, you must die!" Saying this, he ordered a musket to be fired (which was the arranged signal) and a blow was given to them which they will remember forever, for we killed many of them and burned others alive, so that they gained nothing from the promises of their false Idols.

In less than two hours our friends, the Tlaxcalans--who we had kept outside the city--arrived. They fought very bravely in the streets where the Cholulans defended them. After accessing [the streets], they [the Tlaxcalans) went quickly about the city, plundering and taking prisoners and we could not stop them. The next day more companies arrived from the region of Tlaxcala. These men, fierce enemies of the Cholulans, did great damage; seeing this, Cortés and the other captains, filled with pity, restrained the Tlaxcalans from doing further damage. Cortés ordered Pedro de Alvarado and Cristóbal de Olid to bring him all the Tlaxcalan captains together. They did not take long in coming; then he ordered them to gather together all their men and return to their camp in the countryside, and this they did and only the men from Cempoala remained with us.