Link to enlarge K6042 (Las Bocas - Ceramic Vessel) THE FOUNDATION RESEARCH DEPARTMENT

The Mayan Calendar, The Solar - Agricultural Year, and Correlation Questions
By David Bolles
(published in Mexicon in September, 1990)

It is generally accepted by Mayanists today that the Mayan calendar was a "floating" calendar, in which no attention was given to keeping the calendar in sync with the solar - agricultural year. As Michael Coe in his book The Maya puts it, the Maya had "a ’Vague Year’ of 365 days, so called because the actual length of the solar year is about a quarter-day more, a circumstance that leads us to intercalate one day every four years to keep our calendar in march with the sun, but which was ignored by the Maya." 1   Earlier Thompson wrote that "The Maya made no attempt to intercalate days in the count of the years to bring the year of 365 days into conformity with the solar year. Such a correction would have played havoc with the whole orderly plan of the calendar and would have disorganized the elaborate system of lowest multiples of different time cycles, which were of the highest importance for divinatory and ritualistic purposes." 2 

However, while working with the Yucatecan Mayan Colonial literature such as the Books of Chilam Balam one gets the distinct impression that the Mayan scribes who originally wrote this material were well aware of how their calendar worked. Among the various points about their calendar there are two assertions in particular which stand out: 1) that the first day of Poop fell on July 16th of the Julian calendar (= July 26th of the Gregorian calendar in the 1500’s and 1600’s), and 2) that the katun which they were using, often called an Ahau Katun, was composed of 24 years. It is the purpose of this paper to look at these two assertions with the hope that other people thinking about the calendar question will have this additional material to work with. 3 

From various indirect references throughout the Books of Chilam Balam it seems that much of the original material incorporated in the various Books of Chilam Balam was first written between 1593 and 1629. Furthermore, the scribes would from time to time note that the material they were writing down in Latin script was transcribed by them from hieroglyphs. In reading through the various Books of Chilam Balam one finds such phrases as lay bin u hokzah tu uooh anahte bin (thus it was said that he took it (that is, the passage in which this line appears) out of the hieroglyphs of the book 4 ), tin hokzah ti uooh (I took this out of the hieroglyphs 5 ), and ca ix u xocahoob tu uoohil (and thus they read it in the hieroglyphs 6 ). It would thus seem to be a reasonable assumption that the person or persons who originally wrote the Yucatecan Mayan Colonial texts from which the various Books of Chilam Balam were formed were able to read hieroglyphs and in fact were often transcribing hieroglyphic texts when writing down the material in Latin script. From these statements a conjecture can be made that while these scribes were active a half century or more after the conquest, the fact that they could still work with hieroglyphs would indicate that they still retained enough of their Mayan culture to also be knowledgeable of how their calendar worked.

A look at two particular texts from this Yucatecan Mayan Colonial literature would help to illustrate the point of view of these Mayan scribes concerning how they thought their calendar worked. The first text, U Kinil Uinaloob (the days of the uinals), illustrates assertion 1, and the second text, U Buk Xoc Ahau Katun, (the count of the Ahau Katun) illustrates assertion 2.


  1. Coe, 1980, page 44.
  1. Thompson, 1960, page 121.
  1. Throughout this discussion references are made to line numbers. These lines numbers are from the book Post Conquest Mayan Literature in which parallel texts from the various Books of Chilam Balam are transcribed in parallel so that they could be more easily compared in preparation for an effort to get back to an original reading of the texts. By consulting these line numbers in this book the various source texts can be located, and if need be the exact location of the original text from which these lines came can be found and compared with what is given here.
  1. Line C435.
  1. Line C560.
  1. Line J431.

Click to download the report in PDF format:

The Mayan Calendar, The Solar - Agricultural Year, and Correlation Questions  (232 KB)

The PDF files require Adobe Acrobat Reader.
To download the latest version, click the Get Acrobat Reader button below.

Get Acrobat Reader

Return to top of page