The religious rites were elaborate and prescribed with minuteness. Priests and priestesses were vowed to the cult of certain deities. Their duties consisted in sweeping and decorating the temples, in preparing the sacrifices, and in chanting at certain periods of the day and night. The offerings were usually of quails, rabbits or flowers, but, especially in Tenochtitlan, human sacrifices were not infrequent. The victims were slaves or captives taken in war. At times their flesh was distributed to the votaries, and was consumed as part of the ceremony; but as this was a rite, the Aztecs cannot be said to have been anthropophagous. The priestly class had charge of the education of the youth of the better class. This was conducted with care and severity. Large buildings were set apart for the purpose, some for boys, others for girls. The boys were taught martial exercises, the history of the nation, the chants and dances of the religious worship, forms of salutation, the art of writing, etc. The girls were instructed in household duties, the preparation of food, the manufacture of garments, and the morals of domestic life.[155] The literature which represented this education was large. It was preserved in books written upon parchment, or upon paper manufactured from the fibrous leaves of the maguey. This was furnished in great quantities from different parts of the realm, as much as 24,000 bundles being required by the government annually as tribute. A book consisted of a strip of paper perhaps twenty feet long, folded like a screen into pages about six inches wide, on both sides of which were painted the hieroglyphic characters. These were partly ideographic, partly phonetic; the latter were upon the principle of the rebus, conveying the name or word by the representation of some object, the word for which had a similar sound. I have called this the _ikonomatic_ method of writing, and have explained it in detail in several essays on the subject.[156] Their calendar recognized the length of the year as 365 days. The mathematical difficulties in the way of a complete understanding of it have not yet been worked out, and it may have differed in the various tribes. Its elements were a common property of all the Nahua peoples, as well as many of their neighbors; which of them first devised it has not been ascertained. UTO-AZTECAN LINGUISTIC STOCK. _a. Shoshonian Branch._