Maya Cycles of Time: Later Dating Schemes

Sandra Monteferrante (Dowling College)


In the Late Classic era, Long Count dating passed out of use in favor of an abbreviated system for commemorating the end of a katun or 7,200-day period. A Long Count katun-ending date of  2 Ahau  13 Tzec

was reduced to

Katun 16  2 Ahau  13 Tzec.

The loss of specificity is not as great as it seems because of the redundancy inherent in the dating system. A given period-ending date is exact within a cycle of nearly 19,000 years, a time period well in excess of the 13-baktun Great Cycle of 5,128 years.

Unfortunately, by the Late Post Classic (900–1500 CE) era, well before the arrival of the Spanish, another abbreviation for katun endings reduced the accuracy to within the much smaller period of 260 years. This method, dubbed the Short Count, suppressed all katun-ending references except the Tzolkin day. The katun-ending date above,  2 Ahau  13 Tzec,

was reduced to

Katun 2 Ahau.

It is indistinguishable from  2 Ahau  13 Mac,

some 256 Gregorian years later.

The table below shows how a particular date might appear. Note the variation in codex and stela glyph style. There is significant variation in styles among various archeological sites and even on the same site at different times. This makes general decipherment particularly challenging.  2 Ahau  13 Tzec

Long Count date

Katuns must end on an Ahau day because the first katun did and each Ahau day reoccurs every 20 days. The 13 day numbers, however, are not sequential for katun endings. The length of a katun in days, 7,200, is 11 or –2 (mod 13). Thus successive katun-ending Ahau days are 13 Ahau, 11 Ahau, . . ., 1 Ahau, 12 Ahau, 10 Ahau, . . . These dates, arranged in a wheel, constituted the prevailing calendar at the time of the Spanish Conquest. In Figure 9 is de Landa’s version of the Maya calendar.

De Landa Katun wheel
Figure 9. De Landa's sketch of the Round of the Katuns. Wikimedia Commons.

The Short Count is a major reason for the unresolved problem of correlating the Maya and European calendars. Short Count dates are correlated to European dates; the problem is correlating prevailing Short Count with ancient Long Count dates. The generally accepted correlation places the Long Count katun ending of  13 Ahau  8 Xul

on the Gregorian date of November 12, 1539.