twenty days constitute a current month, it is apparent that every month in a given year must begin with the same day. However, the introduction of the five intercalary days at the end of the year, changed the initial day on which the months of the different years began. In reckoning the Katun it is further observed that the numeral which indicates the day of the week (of thirteen days) which falls upon the first of a given month, varies. Supposing the month to begin on Kan and the numeral of the first day to be 1, the numerals indicative of the days of the week (composed of thirteen days) falling on Kan throughout the eighteen months, would be, 8, 9, 3, 10, 4, 11, 5, 12, 6, 13, 7, 1, 8, 2, 9, 3. The Katun year consisted, as we have seen, of twenty-eight weeks of thirteen days each, and _one additional day_, making in all 365 days. If the year commenced with number one of the week, the additional day (the 365th) caused it to end on the same number. The ensuing year would then begin with number two, and so on through the thirteen numbers of the week, as follows: 1. Kan, 2. Muluc, 3. Ix, 4. Cauac, 5. Kan, 6. Muluc, 7. Ix, 8. Cauac, 9. Kan, 10. Muluc, 11. Ix, 12. Cauac, 13. Kan, thus completing an indiction or week of years. The same combination of names and numerals can only occur after the lapse of the Katun or cycle comprising four of these indictions or fifty-two years. Not only the years of the week, but also the indictions themselves were named by the four initial symbols. The first indiction of each Katun being named Kan, the second Muluc, the third Ix, and the fourth Cauac. The completion of a Katun or fifty-two years was celebrated with feasts and rejoicings as an event of great moment. A monument was reared as a memorial of the event. It is not impossible that the great number of pillars, observed by Stephens at Chichen-Itza were of this character, serving as landmarks to Maya chronology.[630]