Maya Calendar - Overview

Overview

The Maya calendar consists of several cycles or counts of different lengths.

The 260-day count is known to scholars as the Tzolkin, or Tzolk'in in the revised orthography of the Academia de las Lenguas Mayas de Guatemala. The Tzolk'in was combined with a 365-day vague solar year known as the Haab' to form a synchronized cycle lasting for 52 Haab', called the Calendar Round. Smaller cycles of 13 days (the trecena) and 20 days (the veintena) were important components of the Tzolk'in and Haab' cycles, respectively. The Calendar Round is still in use by many groups in the Guatemalan highlands.

A different calendar was used to track longer periods of time, and for the inscription of calendar dates (i.e., identifying when one event occurred in relation to others). This is the Long Count. It is a count of days since a mythological starting-point. According to the correlation between the Long Count and Western calendars accepted by the great majority of Maya researchers (known as the Goodman-Martinez-Thompson, or GMT, correlation), this starting-point is equivalent to August 11, 3114 BCE in the proleptic Gregorian calendar or 6 September in the Julian calendar (−3113 astronomical). The GMT correlation was chosen by John Eric Sydney Thompson in 1935 on the basis of earlier correlations by Joseph Goodman in 1905 (August 11), Juan Martínez Hernández in 1926 (August 12), and Thompson himself in 1927 (August 13). By its linear nature, the Long Count was capable of being extended to refer to any date far into the past or future. This calendar involved the use of a positional notation system, in which each position signified an increasing multiple of the number of days. The Maya numeral system was essentially vigesimal (i.e., base-20), and each unit of a given position represented 20 times the unit of the position which preceded it. An important exception was made for the second-order place value, which instead represented 18 × 20, or 360 days, more closely approximating the solar year than would 20 × 20= 400 days. It should be noted however that the cycles of the Long Count are independent of the solar year.

Many Maya Long Count inscriptions contain a supplementary series, which provides information on the lunar phase, number of the current lunation in a series of six and which of the nine Lords of the Night rules.

A 584-day Venus cycle was also maintained, which tracked the heliacal risings of Venus as the morning and evening stars. Many events in this cycle were seen as being astrologically inauspicious and baleful, and occasionally warfare was astrologically timed to coincide with stages in this cycle.

Less-prevalent or poorly understood cycles, combinations and calendar progressions were also tracked. An 819-day Count is attested in a few inscriptions. Repeating sets of 9-day (see below "Nine lords of the night")associated with different groups of deities, animals, and other significant concepts are also known.