the same name falling in one year; and since 9 goes into 360 without remainder, the commencement of the year coincided with the commencement of the series of "lords of the night." These lords of the night are indicated by the heads or symbols of the following gods: 1. Xiuhtecutli, 2. Itztli, 3. Tonatiuh, 4. Cinteotl, 5. Mictlantecutli, 6. Chalchiuhtlicue, 7. Tlazolteotl, 8. Tepeyollotl and 9. Tlaloc. Nor is this all, a corresponding series of thirteen "lords of day," which however is not similarly composed in all MSS., accompanied the days (omitting the nemontemi), and the influences of the day-and night-lord assigned to each day respectively constituted two additional features for the consideration of the would-be interpreter of the tonalamatl. It is perhaps hardly necessary to state that the reading of the book of days was in the hands of a professional priesthood and required much study to perform correctly.
Since each "month" consisted of twenty days, and there were twenty day-signs, it is obvious that each month in a given year began with the same sign; but since the last month was followed by the five unlucky days, it follows that each year began with a day-sign five days later than the last. Also since 365 is divisible by 13 with 1 as remainder, it follows equally that each year began with a day-number one in advance of the last. Further, since there were twenty day-signs, and five (the least common multiple of 365 and 20) goes into twenty exactly four times, the year began with one of four signs only. Now the year was always distinguished by the sign of the day on which it began, and it is a peculiar fact that the commencement of the year never coincided with the commencement of the tonalamatl. The four signs which give the names to the years are the signs tecpatl, calli, tochtli and acatl, recurring in that order. Whether the day-number entering into the name of the year was that of the first
