The embassy [to Cortés at San Juan de Ulua], consisting of two Aztec nobles, was accompanied by the governor, Teuhtlile, and by a hundred slaves, bearing the princely gifts of Montezuma. One of the envoys had been selected on account of the great resemblance which, as appearing from the painting representing the camp, he bore to the Spanish commander. And it is a proof of the fidelity of the [Aztec] painting, that the soldiers recognised the resemblance, and always distinguished the chief by the name of the “Mexican Cortés.”
William H. Prescott, History of the Conquest of Mexico
[W]hen Motecuhzoma II was elected, the king of Tezcoco, Nezahaulpilli, [declared]: “He placed us in front of a mirror where we must free ourselves.”
Guilhem Olivier, Mockeries and Metamorphoses of an Aztec God: Tezcatlipoca, “Lord of the Smoking Mirror” (trans. by Michel Besson, University Press of Colorado, 2003)
Tezcatlipoca arrived in the guise of a young man at the palace where Quetzalcoatl was secluded. He brought with him a wrapped up two-faced mirror and announced to the guards that he had come to “present his body” to the king of Tollan. The latter was somewhat taken aback by the project: “What’s my ‘body’?” Tezcatlipoca refused to show the mirror to the guards, but Quetzalcoatl agreed to receive him. The “young man” then unveiled his instrument and said: “Know yourself, see yourself, my child, for you will appear in the mirror.” Upon seeing his puffed face and sunken eyes, Quetzalcoatl became frightened and feared his subjects would surely flee if they saw him. He decided to stay in his palace. Tezcatlipoca went out and laughed at his victim. . . .
Quetzalcoatl-Nanahuatl, transformed into the sun in Teotihuacan, reaches the zenith where he becomes the prisoner of the black mirror. Starting with the descent of the star (“the afternoon sun”), he comes even closer to the earth, night, and matter. Quetzalcoatl has then become a lunar personage, similar to Tlaloc and also to the old god of fire, and he possesses a body that Tezcatlipoca himself reveals to him in a mirror. . . . As a young man, Tezcatlipoca mocks the old Quetzalcoatl. The Lord of the Smoking Mirror would then be the nascent night and the deforming mirror that soils whoever looks into it.
According to [Michel] Graulich, the Mexica king thus hoped to reproduce the episode of the mirror and Quetzalcoatl in Tollan that I have just mentioned. Once confronted with his own image or reflection, Cortés, like the old Tollan king, would have been assimilated with a waning star. The Belgian scholar also supposes that this “human mirror” could have functioned in the same way as the obsidian knife placed in a container of water, which was used to repell the attacks of the most powerful sorcerers. When confronted with their own images, they took flight.
If the Spanish were indeed amazed at the resemblance between Quintalbor and their own leader, obviously Cortés was not worried to have to face his own image.
. . . [T]hey remained so frightened that they never learned who told me about it [the plot against the Spaniards] and I do not believe they will ever rise again, because they believe that I have learned about it through a special craft and thus they think that nothing can remain hidden from me. And indeed, since they saw that, in order to find this path [to Honduras], I used a marine map and a compass . . . they told many Spaniards, and from them in turn I heard it, and even some of them told me directly . . . that in order for me to know their good intentions, they begged me to look into the mirror and the map and that I would see there that they were well disposed to me since I saw all things; I myself had them understand that that was the truth and that, with the compass and marine map, I could see and know and that all things became clear to my eyes.
Fernando Cortés, Third Letter (translated in ibid.)