(I) The Native Codices.—These are paintings executed by native Mexican artists upon agave paper, leather, or cotton. Through the misguided zeal of the early Spanish religious authorities, who regarded them as of diabolic character, only some twelve of these remain to us, the greater number of which possess a mythological or religious significance. In their pages we find representations of many of the principal deities of the Mexican pantheon, as well as illustrations of several passages in Mexican myth, and they frequently depict the tonalamatl or priestly Book of Fate, with its highly complex symbolism. [5] Close familiarity with these manuscripts is indispensable, as they constitute one of the few original sources of our knowledge of the aspect, costume, and insignia of the Mexican deities. All of them have been handsomely, if expensively, reproduced, and these are detailed in the bibliography. Here it is only necessary to remark upon the several theories which have regard to their place of origin. Dr. H. J. Spinden, in his valuable Study of Maya Art, objects that “most of the detailed accounts of religious beliefs and ceremonies that have come down to us refer primarily to the Valley of Mexico, while nearly all the really elaborate codices of a religious nature come from either the Zapotecan-Mixtecan area or from the Maya.” [6] We are not here concerned with the Maya manuscripts, and with regard to the Zapotec and Mixtec examples we have the assurance of Seler, [7] which is founded upon critical evidence of value, that an entire group of these manuscripts—and that by far the most important, the Codex Borgia group—“belongs to a Mexican-speaking people” who inhabited the districts of Teouacan, Cozcatlan, and Teotitlan del Camino, and who, though separated from the Nahua of the Valley of Anahuac at an early period, yet in great measure retained the ancient beliefs common to both. Nearly all of the deities represented in this group of manuscripts so closely resemble in their aspect, costume, and general symbolism the drawings and descriptions of gods known to have been worshipped in the Mexican area proper, as to make it positively certain that they represent the same divine beings with merely trifling differences of detail due to local environment. The separation of the Nahua of the Plateau of Mexico and those of the more southerly region was of such duration as to justify the belief that their religious ideas had diverged considerably. But the subsequent conquest of the southern area by the Northern Nahua must have resuscitated old common beliefs among their kindred in the south, and weakened the ideas they had adopted or developed in that environment. This is proved by the considerable variation in type between the oldest southern pottery representing what are presumably divine forms and the pictures of the gods in the later manuscripts of the Codex Borgia group.