From Fray Bernardino de Sahagún, The Florentine Codex, Book 12, Chapter 1 (Mexica)

Ten years before the Spaniards first came here, a frightening omen appeared in the sky. It was like a large glowing blaze. It seemed to pierce the sky itself, very wide at the base and narrow at the top. It extended to the very middle of the sky, to the very heart of the heavens. When it shone in the east in the middle of the night, it burned so bright one could believe it was dawn. The blaze appeared at midnight and burned till the break of day, then it disappeared from view. When the day broke, the sun effaced it. This omen was visible each night for a year, beginning the year 12-House. When it appeared at midnight, everyone shouted and hit their hands against their mouths; they were frightened and asked themselves what it could mean.

The second omen which appeared was that the temple of Huitzilopochtli burst into flames of its own accord and flared greatly. When the fire appeared, the squared, wooden pillars were already in flames; from within them emerged tongues and tassels of flames that speedily consumed all of the building's beams. When the fire appeared, people shouted: "Mexicanos, hasten here, come and extinguish the flames, bring your water jugs!" They came, but when they threw water on the blaze it only exploded more. They could not put it out, and the temple burned to the ground.

The third omen was that a temple was struck by a lightning-bolt. It was only a straw hut, the temple of Xiuhtecuhtli in the place known as Tzumulco. It was believed to be an omen because the sun was shining and it was not raining hard that day, only a drizzle, and no thunder was heard.

The fourth omen was that while the sun was still shining. a comet fell, divided into three parts. It flashed out from the west and raced straight to the east, looking like a shower of sprinkling, glowing coals, and its tail reached a far distance. When the people saw it, there was a great outcry, like the sound of rattles.

The fifth omen was that the water of the lake boiled up; the wind had nothing to do with it. It was as if it were boiling with rage and made exploding sounds and rose high in the air and reached the foundations of the houses until the houses collapsed. This was the great lake [Lake Texcoco] which surrounded us here in Mexico.

The sixth omen was that often a woman was heard weeping and shouting. She cried out loudly at night, saying "Oh, my children, we are about to go." At other times she cried: "Oh my children, where shall I take you?"

The seventh omen came when water people were hunting or snaring and captured an ash-covered bird, like a crane. They went to the Tlillan calmecac to show it to Moctezuma; it was past noon, but still daytime. On top of its head was something like a strange mirror, round, circular, and it appeared to be pierced in the center, where one could see the sky, the stars, and the Firedrill [mamalhuaztli or Caster and Pollux constellation]. Moctezuma took it as a great and evil omen when he saw the stars and the mamalhuaztli. And when he looked at the bird's head a second time a little further, he saw a crowd of people coming, armed for war on the backs of deer. Then he called for the soothsayers and sages, and asked them: "Do you not know what I have seen? a crowd of people coming." But when they began to answer him, all had vanished, and they could tell him nothing more.

The eighth omen was that monstrous beings appeared, deformed men with two heads but only one body. They took them to the Tlillan calmecac and showed them to Moctezuma; but when he looked at them, they disappeared.< p>