From Fray Bernardino de Sahagún, Florentine Codex, Book 12, Chapter 39

Here it is told how when [the Spaniards] had forced them to the wall [of fortifications around the city], there appeared and was seen a blood-colored fire that seemed to come from the sky. It appeared like a great blazing coal as it came.

And when night had fallen, it rained and sprinkled off and on. Then in the deepest darkness of the night there appeared in the heavens what was like a fire. It looked and appeared as if it was coming from the sky, like a whirlwind; it went spinning around and revolving. The the blazing, turning ember seemed to explode; it was as if embers burst out of it--some very large, some very small, some like sparks. It rose up like a coppery wind; it arose, crackling, snapping, and exploding loudly. Then it circled the walls at the water, heading toward Coyonacazco, then it went into the midst of lake and disappeared there. No one struck his hand against his mouth; no one uttered a word.

And on the next day, nothing more happened. All remained [quiet], and also our foes remained [quiet]. But the Captain [Cortés] was watching from a rooftop at Amaxac--from the roof of the house of Aztauatzin under a canopy. It was a many colored canopy. He was looking toward the common people; Spaniards swarmed about him; they were consulting among themselves.

For our part, we gathered in Tolmayecan and debated what to do, what we should offer as tribute, and how we should submit to the Spaniards.

[The chapter then lists who was at the meeting. It included Cuauhtémoc, the current Mexica emperor, and several noblemen.]

Then, Cuauhtémoc left on a boat. Only two [men] accompanied him, went with him: Tepotzitoloc, a seasoned warrior, and Iaztachimal, Cuauhtémoc's servant, and there was one person who rowed for them, named Cenyaotl.

When they were about to take Cuauhtémoc, all the people wept, saying, "There goes the young Prince Cuauhtémoc, going to surrender himself to the gods, the Spaniards."