Posted by: Johan Normark | November 2, 2010

2012: The Maya calendar correlation problem pt 1

I have now read Gerardo Aldana’s essay ”The Maya calendar correlation problem” that I mentioned in an earlier blog post. It is also a long essay and I will make it into two or three blog posts. Although the essay does not concern the 2012 phenomenon as such I file it under that category on this blog since it shows that the correlation problem still is with us. John Major Jenkins, one of the main proponents for an “alternative” interpretation of the Maya calendar, has commented on Aldana’s research but without actually reading the essay. Not only is Jenkins’ critique missing the whole issue that Aldana raises, but Jenkins (and other “2012ers”) will for sure not give up their beloved winter solstice alignment. That would be devastating to their business.


Eric Thompson

The essay takes a history of science approach and “examines the individual histories of Mayanist considerations of the Dresden Codex Venus Table, the Landa equation, the Katun sequence in the Chronicle of Oxkutzcab, and a subset of the calendric data in the Books of Chilam Balam” (p. 2). I highly recommend everyone to read the essay as it shows how some issues can become “black boxed” in the Latourian sense. Aldana shows that “critical aspects of the problem’s genealogy […] have been buried within the literature, and so rendered invisible to late 20th and early 21st century scholarship” (p. 2). The main focus is set on Eric Thompson and Floyd Lounsbury and their formulation and solution of the problem. It turns out that Thompson still affects Mayanist research, 35 years after his death.

 In this first post I basically mention the various calendars and astronomical data that are under discussion in Aldana’s essay. The Calendar Round (CR) consists of a 260 day long cycle generally called tzolkin (chol qiij) and a 365 day long cycle generally called haab (haab’). Together these cycles form the greater CR of roughly 52 years. The CR appears to have been the same at all known sites throughout the lowlands during the Classic period. However, there were changes in practice sometime between the early Postclassic period and the late Colonial period as can be seen in the so-called Yearbearers which are different in later periods. Hence, there were some slippage between the tzolkin and the haab. During Classic times the CR were often combined with Long Count (LC) dates. Thus, the aim of the correlation issue is to match the CR and LC dates with equivalent dates in the Julian calendar (not the Gregorian calendar since it was introduced in 1582). This is the Ajaw equation and it is expressed as: LC + X = JD. X is the Ajaw constant and JD is the Julian Day number.

During the Terminal Classic the Maya began to use a Katun Count (aka the Short Count) that named a katun (a 20 years long period) after the final day in the tzolkin calendar. Hence 13 Ajaw 18 Yax was called a Katun 13 Ajaw. However, sometime between the late Terminal Classic period and the early Colonial period the Maya changed this system from being part of the larger Baktun count of the LC to simply become a cyclical format with 13 katuns in each cycle (the may cycle in Prudence Rice’s model). Thus, can we be sure that there is strict continuity through these changes in calendar practices? Can there even be a maintained synchrony across the Maya area without the LC? It is doubtful in my opinion.

During the Classic period the LC was accompanied by the Lunar Series. These are fairly consistent from site to site and most of the moon ages were probably derived from observation. Hence, any proposed calendar correlation must predict the moon ages within the Lunar Series. What is needed then is the recording of moon ages and calendar dates in later Maya documents, such as the Dresden Codex. Unfortunately there is no recognizable historical eclipse within the Eclipse Table of the Dresden Codex. The table only appears to record possible events or warning dates, not observed moon ages with a known historical anchor.

It is the Venus Table in the Dresden Codex that has played a crucial role in the correlation issue. The Venus Round (VR) is given as 584 days in the Dresden Codex. It counts them off for roughly 104 years. However, the true synodic period of Venus is 583,9214 days. This discrepancy is believed to have been corrected by the use of correction intervals in order to make up for the accumulating error. Many Mayanists have proposed schemes for “integrating correction intervals with uncorrected VR in idealized schemes, but for the most part, these proposals rely on the invocation of a specific calendar correlation…” (p 11). It is here where the problems begin and Aldana shows how people have twisted and bended the empirical data in order to fit their own correlation constant. To be continued…



  1. There has been a long standing debate among scholars as to the exact correlation of the Mayan calendar with the European calendar. A number of researchers including my father Maya archaeologist Stephan F. de Borhegyi, (better known as Borhegyi), and most notably E. Wyllys Andrews (1960, 1965, 1965c, 1968, 1973) have presented convincing archaeological evidence favoring the correlation developed by Herbert Spinden. It is the Spinden correlation that sets all Maya dates 260 years earlier than the G.M.T. correlation.
    According to archaeologist Michael Coe, only two correlations meet the requirements of both dirt archaeology and specific dates. Bishop Diego de Landa, who wrote his chronicles shortly after the Spanish Conquest, tells us of an event which fell on a certain day in the 52 year calendar round that he said coincided with July 16th, 1553 in the Julian Calendar. This calendar, developed by the Romans during the reign of Julius Caesar was used in Europe until it was revised in the year 1582 during the papacy of Gregory the X!!!, after which it was known as the Gregorian Calendar. This is the calendar now used in most countries in the world. Another date, recorded in the native chronicles known as the Chilam Balam, set the date of the Spanish foundation of the city of Merida in Yucatan in the Julian calendar date of January 1542.
    In many ways the Spinden correlation, which uses archaeological evidence from both the Maya lowlands and the southern highland regions, fits the archaeological and historical requirements better than the GMT correlation. In 1951 and 1955 samples of Sapodilla wood from dated lintels (beams) spanning Late Classic Mayan doorways at Tikal were tested by radiocarbon dating, These tests favored the Spinden correlation. More tests were performed in 1960 which now favored the GMT correlation. So Maya scholars came to a consensus favoring the Thompson or GMT correlation over the Spinden correlation. To this day the debate on the subject has never ceased. Due to various discrepancies in the tests, radiocarbon dating has not resolved the matter as to which correlation is correct.
    For new evidence favoring the Spinden Correlation visit
    If the Spinden interpretation is correct, it establishes the beginning of the world at 3374 B.C. That, in turn, places the “so-called” end of the Mayan Calendar at 1760 rather than 2012. In other words, contrary to much contemporary hype, the end of the “fifth world” may have already ended. If so, there was no Armageddon and the Mayan Calendar simply began another cycle.
    Carl de Borhegyi

    • Thanks for the link, I did not know about your website. I will look into it. The main problem with the correlations is that they are based on the idea of continuity of the tzolkin from the Classic period until the Colonial period. I will discuss that in the following post(s) on Aldana’s essay.

      I believe that the whole idea of fifth world/Sun/cycle, etc. basically is a mixture of Aztec Postclassic beliefs and the Maya Long Count (one of the reasons why we often see the Aztec calendar stone in 2012 publications). There is no evidence that the Classic or Late Formative Maya believed in four earlier creations, that simply do not fit recordings of pre-era dates:

      This reminds me that I had planned to discuss Gronemeyer and MacLeod’s interpretation of Monument 6 at Tortuguero.

  2. Good read Johan. I’m excited for the follow up!

  3. Thanks for all these analyses. I noted something interesting in the link you provide to John Major Jenkins’ comments on Professor Aldana’s work. Jenkins says that for 20 years, he (Jenkins) has been saying that there is no evidence that the Maya thought about 13 baktun cycle endings as signaling apocalyptic events.

    Jenkins is mistaken. As documented by, (, Jenkins clearly attributed apocalyptic beliefs to the Maya in his “magnum opus”, Maya Cosmogenesis 2012 (MC2012). For example,

    “What is the metaphysical meaning of the end-date alignment? My interpretation is derived as much as possible from Maya iconography and calendar tradition. According to Maya calendar cosmology, the end of time and space is, December 21, 2012.” (p. 210)


    “The ancient Maya understood that the future alignment would have apocalyptic effects, and designed their World age mythology to remind us of what is essential, and what can help us through the transformation.” (p. 214)

    Although he promotes MC2012 as essential for understanding his theories, there’s a lot in that book that Jenkins himself appears to have forgotten.

  4. As far as I remember Jenkins also made some connections between the Maya “black transformer/hole” and the true black hole in the center of the galaxy…

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  6. […] a friend,” as Kristin Sewell stated. Blogging gives new scholars a chance to speak out, to debunk 2012 foolishness and to give a little bit back to the public that usually signs our paychecks in one way or another. […]

  7. […] question for this week goes as follows: …Blogging gives new scholars a chance to speak out, to debunk 2012 foolishness and to give a little bit back to the public that usually signs our paychecks in one way or another. […]


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