Maya Long Count Calendar: Origins of Mesoamerican Timekeeping

The Long Count calendar was a system for counting days from a fixed starting point in the mythical past, used in southern Mexico and the Maya region for about a thousand years. Its earliest known date, carved on a monument at Chiapa de Corzo in Chiapas, corresponds to December 36 BC. The Classic Maya later used it to date thousands of monuments with precision to the day, and its cycle ending on 21 December 2012 became the subject of a worldwide misunderstanding.

How the Long Count works

Most calendars in Mesoamerica repeated in cycles. The 260-day ritual calendar (tzolk’in in Maya) combined 20 day names with numbers from 1 to 13. The 365-day solar calendar (haab’) had 18 months of 20 days plus 5 extra days. Together they formed the Calendar Round, which repeated every 52 years, so a date could not be placed in a longer history.

The Long Count solved this problem by counting days continuously. It used a mostly base-20 system, written as five numbers:

The third place is the exception: 18 winals, not 20, make a tun of 360 days, keeping the count close to the solar year. Modern scholars write dates with dots, so 9.12.11.5.18 means 9 bak’tuns, 12 k’atuns, 11 tuns, 5 winals and 18 k’ins after the starting point.

Numbers, zero and distance numbers

Long Count dates were written with the bar-and-dot numerals used across Mesoamerica. A dot stood for one and a bar for five, so the number 18 was written as three bars and three dots. On Maya monuments the numbers were often combined with glyphs naming each unit, and some scribes replaced the numerals with portraits of gods.

A place-value count like this needs a way to show that a position is empty. Mesoamerican scribes used a special sign for zero, often drawn as a shell in the Maya codices. Together with the Babylonian and Indian systems, this is one of the few independent uses of zero in the ancient world, although the Mesoamerican sign served mainly in calendar counts.

The Maya also used “distance numbers”, which counted forward or backward from one date to another. A monument might record a king’s accession and then add a distance number to reach an anniversary or a battle. This let scribes link events across many years with exact precision.

The starting point in 3114 BC

The Long Count began on a day written 13.0.0.0.0 4 Ajaw 8 Kumk’u. Using the most widely accepted correlation, called the GMT correlation after Joseph Goodman, Juan Martínez Hernández and J. Eric S. Thompson, this corresponds to 11 August 3114 BC in the proleptic Gregorian calendar. A variant of the correlation places it two days later.

This date was not a historical event. It marked the creation of the present world in Maya mythology, following earlier creations that had failed. Inscriptions at Palenque and other sites describe events at the creation, and some even refer to dates millions of years in the past.

The earliest dated monuments

The oldest Long Count dates do not come from the Maya lowlands but from the Isthmus of Tehuantepec region, Chiapas and the Gulf Coast of Mexico. The earliest securely read example is on Stela 2 from Chiapa de Corzo, Chiapas. Its date, reconstructed as 7.16.3.2.13, falls in December 36 BC, although the first two numbers are damaged and have been restored by scholars.

Stela C from Tres Zapotes, in Veracruz, records the date 7.16.6.16.18, corresponding to 32 BC. The American archaeologist Matthew Stirling found the lower part of the stela in 1939, and the discovery of the upper half in 1969 confirmed the reading of the bak’tun number. Other early examples include the La Mojarra Stela 1 (with dates in AD 143 and 156) and the Tuxtla Statuette (AD 162), both from Veracruz.

These finds mean that the Long Count was probably developed by peoples of the Gulf Coast and the Isthmus, sometimes linked to the later phases of the Olmec tradition, before the lowland Maya adopted it.

Maya use in the Classic period

The Maya made the Long Count central to their monuments. The earliest known dated monument from the lowlands is Tikal Stela 29, with a date corresponding to AD 292. Over the following six centuries Maya cities raised hundreds of stelae and altars with Long Count dates, recording births, accessions, wars and rituals of kings.

A full Maya date was often introduced by a large glyph and accompanied by additional information, such as the Calendar Round date, the lord of the night and the phase of the moon. Portable objects carried dates too, such as the Leiden Plaque, which records a date in AD 320.

The last known Long Count date on a monument comes from Toniná in Chiapas and corresponds to AD 909. By then many lowland cities were in decline. Later Maya, including those who wrote the books known as codices, used a shorter count based on k’atuns.

Decipherment

Spanish sources from the 16th century preserved knowledge of the 260-day and 365-day calendars, but the Long Count was forgotten. In the 1880s the German librarian Ernst Förstemann worked out how it functioned by studying the Dresden Codex, a Maya book held in Dresden.

The American journalist Joseph T. Goodman proposed in 1905 a correlation between Maya and European dates. It was refined by Juan Martínez Hernández and then J. Eric S. Thompson in the 1920s and 1930s. Radiocarbon dating of wooden lintels from Tikal later supported the GMT correlation, which most scholars now use.

The 2012 misunderstanding

The date 13.0.0.0.0 recurred on 21 December 2012, completing 13 bak’tuns since the start of the count. In the decades before, books, films and websites claimed that the Maya had predicted the end of the world or a great transformation on that day.

No ancient Maya text makes such a prediction. Only two known inscriptions mention the 2012 date: Monument 6 from Tortuguero, which refers to the descent of a god, and a carved block from La Corona published in 2012. The Maya also wrote about dates far beyond 2012: an inscription at Palenque refers to a date in AD 4772. Scholars such as Anthony Aveni and David Stuart explained that the bak’tun ending was a cycle completion, much like a millennium in the modern calendar.

Timeline

• 11 August 3114 BC: Mythical starting date of the Long Count (GMT correlation).
• December 36 BC: Earliest securely read Long Count date, on Chiapa de Corzo Stela 2.
• 32 BC: Date on Tres Zapotes Stela C.
• AD 292: Tikal Stela 29, the earliest dated lowland Maya monument.
• AD 909: Last known monumental Long Count date, at Toniná.
• 1880s: Ernst Förstemann explains the system from the Dresden Codex.
• 1905: Joseph Goodman proposes a correlation with the European calendar.
• 21 December 2012: Completion of the 13th bak’tun.

Why it matters

The Long Count is one of the most precise calendars of the ancient world, counting days without interruption across centuries. It allows historians to date Maya events exactly, something rare for ancient societies. Its early examples also show that writing, mathematics and astronomy were developing across southern Mexico two thousand years ago.