The Calendar Correlation Problem in Mesoamerican Astrology Explained

by Bruce Scofield

The existence of the 260-day count in Mesoamerica, the count that contains 13 repetitions of the 20 day-signs, extends back at least 2,500 years. This count or calendar, as it is generally called, is really a remarkable astrological instrument. It is an arrangement of blocks of time (days and groups of days) that resonate with both planetary cycles and life on this planet. It is a kind of biorhythmic scale. The Maya call this count the Tzolkin, the Aztecs the Tonalpouhalli. In my writings, I refer to it as the 260-day astrological calendar. It is not connected to the seasons and therefore does not require a periodic leapday correction. But in order to know when a particular day arrives, we must either keep daily records of the passage of days (which is what the indigenous Maya do), or have a method of correlating it with the Western calendar.

One way of correlating the 260-day astrological calendar with the Western calendar is to link it to a Julian date. Historians and astronomers have numbered all the days, as far back as several millennia before the Common Era, each day having a Julian day number. If we know the Julian number of an event, and we have our two calendars linked to this system, then we can move dates back and forth between calendars.

Nearly all researchers now agree that the zero date of the Long Count (a.k.a. the Mayan Calendar) began on Julian date #584,283 which was August 11, 3114 B.C. (By the way, 3114 B.C. is the same as -3113). This correlation has come to be known as the Goodman-Martinez-Thompson correlation (G.M.T.), named for the men who struggled for many years with this problem and eventually reached a consensus. Today, the G.M.T. correlation of Julian Day #584,283 with 4-Ahau as the most accepted linkage between the calendars of the West and Mesoamerica.

One of the primary supports for the G.M.T. correlation comes from the many Classic Maya inscriptions. On their stelae and other surfaces, the Maya often recorded the dates of events such as coronations and battles. Many of these inscriptions also include information on significant astronomical events, including con-junctions between planets and turning points in planetary cycles, that occurred at the same time. Using astronomical tables and astronomical software, researchers can locate exactly when, in terms of the Western calendar, these events occurred. The consistency of the dates in the Maya inscriptions indicates that the 260-day count was not tampered with. Other calendars were changed and alternative sets of yearbearers were used, but the 260-day count, much like the 7-day week in the West, never skipped a beat or was affected by a leap day.

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Additional support for the G.M.T. correlation comes from Spanish accounts around the time of the Conquest. During the Spanish invasion of Mesoamerica a few writers noted specific dates in both the Western calendar and in the native 260-day count. When these are compared with the G.M.T. correlation they check out perfectly. The date that Cortes took Tenochtitlan was recorded as both 1-Serpent/Chicchan and August 13, 1521, an exact correlation. Also, Friar Diego de Landa noted that July 16, 1553, was 12-Kan, just one day off from the G.M.T. correlation. Many researchers believe the friar had actually made a mistake in recording this date.

The oral tradition of the Quiche Maya also supports the G.M.T. correlation. According to the G.M.T. correlation, the day 4-Ahau, or 4-Flower occurred on Julian Day #584,283. If this is so, then the cycling of the 260-day astrological calendar can be projected to the present day. When this is done, the results are the same as the count used by the Quiche Maya of Guatemala, whom many believe to be the keepers of the "true count." Once a Julian Day correlation has been established, it is relatively easy to bring the 260-day astrological calendar into modern times.

In summary, the archaeologists, archaeoastronomers, historians, and present-day Quiche Maya all agree on the correlation between the Western calendar and the 260-day astrological calendar. This is the G.M.T. correlation in which Julian Day #584,283 is equivalent to the day 4-Ahau in the 260-day astrological calendar. Also, a majority of astrologers trained in Western astrology who have studied the 260-day calendar, including myself, have found the G.M.T. correlation to be the one that "works." Other correlations do not produce the dramatic results in both personality description and forecasting that the Julian Day #584,283 linkage does.

Several other calendar correlations have been proposed. Linda Schele and David Friedel, in their books "Forest of Kings" and "Maya Cosmos," use a correlation proposed by Floyd Loundsbury, that differs from the generally accepted G.M.T. correlation by 2 days. Not many other researchers agree with his reasons for this correlation, however. Over the years I've met some indigenous peoples living near Mexico City who use correlations that vary widely from the G.M.T. correlation. Jose Arguelles, author of "The Mayan Factor," and the followers of his product "Dreamspell," use a correlation that loses one day every four years. Between 1992 and 1996 it differed from the G.M.T. correlation by 52 days. Between 1996 and 2000 it will differ by 51 days. The Maya and other Mesoamerican cultures, who viewed both each day and the order of the signs as sacred time, would probably be appalled at the idea of skipping a day every four years. They didn't skip days, which makes the Dreamspell/New Age correlation appear to be something other than Mayan.

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Readers who wish to examine the correlation question in more detail are referred to the following books:

Edmonson, Munro S. The Book of the Year: Middle American Calendar Systems, Salt Lake City: University of Utah Press, 1988.

Jenkins, John Major. Tzolkin: Visionary Perspectives and Calendar Studies, Garberville, CA: Borderland Sciences, 1994.

Jenkins, John Major. Maya Cosmogenesis 2012, Santa Fe: Bear & Company, 1998.

Thompson, J. Eric S. Maya Hieroglyphic Writing: An Introduction, Norman: University of Oklahoma Press, 1960.

Bruce Scofield is the author of Day-Signs: Native American Astrology From Ancient Mexico and Signs of Time: An Introduction to Mesoamerican Astrology. His website is

© 2006 Bruce Scofield

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