From Fray Bernardino de Sahagún, Florentine Codex, Book 12, Chapter 24 (Mexica)

Here it is told how the Spaniards and those of Tlaxcala came out and fled from Mexico by night.

When night had fallen, when midnight came, the Spaniards came out, in compact formation, along with all of the Tlaxcalans. The Spaniards went ahead and the Tlaxcalans followed, covering the rear like a wall [of protection]. They carried a wooden portable bridge[s]; they laid it down a canal and crossed over it.

In that season it was raining, drizzling, some light drops. They were able to cross several canals at Tecpantzinco, Tzapotlan, and Atenchicalco. But when they got to Mixcoatechialtitlan, the fourth canal, then it was seen that they were leaving. A woman fetching water saw them, and at that moment shouted, saying, "Mexicanos! come running! Your enemies have already left! They are slipping away!" Then a man screamed from the temple of Huitzilopochtli; his cries spread everywhere, everyone heard him. He said, "Oh warriors! Oh Mexicanos! your enemies are coming out! Hasten here by war boat and along the roads!"

And when it was heard, there was an outcry, and the war boatmen emerged. They hurried; they paddled hard, the boats hit and bumped one another. They headed toward Mictlantonco, toward Macuilcuitlapileo. And from both sides, the war boats attacked [the Spaniards]. The war boats of Tenochtitlan and the war boats of Tlatilulco rushed upon them. And some came on foot, direct to Nonoalco, heading toward Tlacopan to try to cut them off, to stop their retreat. Then those who manned the boats hurled their barbed darts at the Spaniards; from both sides, darts fell on [the Spaniards]. But the Spaniards also shot arrows at the Mexicas; they shot with iron bolts and guns. There were deaths on both sides. The Spaniards and Tlaxcalans were shot with arrows; the Mexicas were shot with arrows [and guns]. And when the Spaniards had arrived at Tlaltecayoacan, where the Toltec canal is, it was as though they had fallen off a precipice. They all fell, those of Tlaxcala, those of Tliliuhquitepec, and the Spaniards, and the horses, and some women. Soon the canal was completely full of them, full to the banks. But those who came at the rear just passed and crossed over on people, on bodies.

When they reached Petlacalco, where there was another canal, very slowly, cautiously, gradually, they passed upon the wooden portable bridge. Here they restored themselves, caught their breath, and revived their valor.

And when they had reached Popotlan, it was dawn and light was spreading. They continued coolly, they continued into the distance ready for combat. But the Mexicas arrived shouting at them, surrounding them, hovering around them. They captured some Tlaxcalans as they went, they killed some Spaniards. But Mexicas and those of Tlatelolca were [also] killed; there was death on both sides. They drove the Spaniards to Tlacopoan, then they drove them from Tlacopan. And when they had driven them to Tiliuhcan, to Xocotliyohuican, at Xoxocotla, Chimalpopoca, son of Moctezuma, died in battle. They came upon him hit by a barbed dart, wounded.

[In the same place] Tlaltecatzin, lord of the Tepaneca, who had been guiding the Spaniards and had gone ahead to show them the route, also died.

Then they crossed the Tepçolatl [a small river]. They crossed and forded the water there at Tepçolatl. Then they climbed up to Acueco and stopped at Otoncalpolco, [where] wooden walls [served as] barricades [around] the courtyard. There they refreshed themselves; there they caught their breath; there they revived. There, the people of Teocalhueyacan came to meet them, to guide them [to safety].

When the Spaniards reached Tlaltecayoacan, where the Toltec Canal is, it was as though they had fallen off a precipice; they filled an abyss. There all fell, those of Tlaxcala, those of Tliliuhquitepec, and the Spaniards, and the horses, and some women. The canal was completely full of them, full, clear to the banks. But those who came last just passed and crossed over on men, on bodies.