This period of 52 years was called by the Indians _Katun_, and at its conclusion great feasts were celebrated, and a monument was raised, on which a large stone was placed crosswise, as is signified by the word _Kat-tun_, for a memento and record of the cycles, or _Katunes_, that had elapsed. It should be observed, that until the completion of this period, the initial days of the years did not again fall upon the same numbers of the week; for which reason, by merely citing them, it was at once known what year of that cycle was arrived at; being aided in this by the wheel or table on which the years were engraved in hieroglyphics. 8 deg.. _Of the great Cycle of 312 Years, or Ajau Katunes_. Besides the cycle of 52 years, or _Katun_, there was another great cycle peculiar to the Yucatecos, who referred to its periods for dating their principal epochs and the most notable events of their history. It contained 13 periods of 24 years each, making together 312 years. Each period, or _Ajau Katun_, was divided into two parts; the first of 20 years, which was included in a square, and therefore called _amaytun_, _lamayte_, or _lamaytun_; and the other of four years, which formed, as it were, a pedestal for the first, and was called _chek oc Katun_, or _lath oc Katun_, which means "stool" or "pedestal." They considered those four years as intercalated; therefore believed them to be unfortunate, and called them _u yail Jaab_, as they did the five supplementary days of the year, to which they likened them. From this separation of the first 20 years from the last four, arose the erroneous belief that the _Ajaus_ consisted only of 20 years, an error into which almost all have fallen who have written on the subject; but if they had counted the years which compose a period, and noted the positive declarations of the manuscripts that the _Ajaues_ consisted of 24 years divided as above stated, they would not have misled their readers on this point.