Returning to reëxamine the divine title Tezcatlipoca we see that, when interpreted as “the lord of the shining obsidian mirror,” it was the most appropriate title of the lord of the Nocturnal Heaven, which myriads of mirrors reflected each night, throughout the land. It is easy to see how the habit of referring to the Temple Minor, in order to ascertain the positions of the stars, would naturally lead to its being consulted more extensively as an oracle later on. We thus clearly perceive how the lord of the Night, whose priests called themselves “the sons of the Night,” became intimately associated with divination and how the idea of a definite connection between the movements of the stars or human destinies would, in the lapse of centuries, make a deep and indelible impression upon the minds of men. If the obsidian mirror was the symbol, par excellence, of Mexican star cult, there are evidences that the small mirror of polished pyrites was that of the sun-cult. The latter seems to have been employed, in some way or other, for the concentration of the rays of the sun required for the lighting of the sacred fire, at noon, on the days of the vernal equinox and summer solstice. As in Peru, this duty devolved upon the high priest of the Above or the Son of the Sun, a title which undoubtedly pertained also to the Mexican ruler, though not employed so ostentatiously as in Peru. A keen emulation, which may almost be termed an intense rivalry, seems to have existed between the two cults, which Sahagun even goes so far as to designate as two religions. From a chapter of his Historia we even learn that the entire population of Mexico was divided into two halves who respectively belonged to one or the other religion, a fact which naturally affected the position of the two classes of people and had created the native ideas, of an upper and a lower class or caste which will be further discussed. Sahagun’s informants explained to him that, when a child was born, its parents, according to their class, registered it at one of the two educational establishments for the young and took vows to have it educated there as soon as it attained a suitable age. The lower class took their offspring to the Telpuchcalli, where they were dedicated to the service of the community and to warfare, _i. e._, the ruling class. “The ‘Lords, chieftains or elders,’ offered their sons to the Calmecac to be educated for the priesthood.”