Renowned for their accuracy, vision, and place in time, Mesoamerican calendars have long been held to exemplify the early development of indigenous civilizations in North, South, and Central America. A new study has found that some of the great Mesoamerican peoples and cultures, such as the Maya and the Olmec, used the calendar more than 3,000 years ago, around 1100 BC, several centuries earlier than previously thought.
The new study, published in the latest issue of the journal Scientific advances focused on the most famous 260-day cholq’ij calendar (order of days) used by these cultures along the southern Gulf Coast as early as 3,100 years ago. Star ceremonial centers were built to follow this shorter calendar the oldest written evidence of this calendar previously found on painted plaster wall fragments from a Mayan site in Guatemala, between 300 and 200 BC.
Scientists have taken advantage of the use of aerial surveys LiDAR (Light Detection and Ranging) technology over an area of 32,641 square miles (84,516 square kilometers). In addition, these orientations were studied on a digital elevation model (DEM) that was derived from LiDAR. These were processed using ArcGIS software and other types of visualization that crunch LiDAR data to create high-resolution images of the Earth’s surface, even while avoiding dense vegetation such as Amazon rainforest .
The great Mayan complex of Aguada Fénix near Tabasco, Mexico is covered in vegetation that LiDar can penetrate (FranceTV / CC BY SA 4.0 )
The 260-Day Calendar: A Performance of Human Excellence
These explorations revealed something fascinating – more than a hundred architectural complexes were arranged to facilitate timed observations of the rising and setting sun, moon and other celestial objects in accordance with the 260-day calendar.
This calendar does not have months, but rather twenty glyphs and signs, including crocodile, water, deer, grass, and eagle, combined with the numbers 1-13. Combining the two makes 260 days. It remains operational in most parts Mesoamerica even today.
“It is clear that the orientations reflect a complex worldview in which astronomical knowledge conditioned by practical interests was intertwined with religious concepts,” says co-author Ivan Šprajc, who studies Mesoamerican archeology and archaeoastronomy at the Slovenian Academy of Sciences and Arts.
The calendar was not only used to record time and structure the changing seasons. The Jerusalem Post states that the same calendar had a key role in Mesoamerican society, associated with important rituals and religious cosmology and even the anointing of the next generation of children.
Existing knowledge has shown that the Maya diligently studied the Sun and Moon, the planets, the Milky Way and other astronomical phenomena. This included the length of the synodic month and the calculation of the length of the month tropical solar year . The use of 260 days remains unclear, although various theories suggest that numbers 13 and 20 were important to people.
Lidar-based images of two sites with similar land plans, each with 20 edge platforms. (A) San Lorenzo. (B) Aguada Phoenix. Places are aligned with celestial objects using the Mayan 260-day calendar. (Takeshi Inomata / CC BY NC 4.0 )
Orientation and Adjacent Structures: A Study of Ceremonial Complexes
The data yielded 415 different notable ceremonial complexes (out of more than 33,000) dating from 1100 BC to 250 AD. Including Olmec center of San Lorenzo Mexico and recently discovered Aguada Phoenix at a Mexican ranch near the Guatemalan border that may be the largest and oldest known Mayan monumental complex. Smithsonian .
LiDar study of Aguada Fénix to reveal the largest and oldest known Mayan monument complex at present. (Alfonsobuchot / CC BY SA 4.0 )
For the purposes of the study, the astronomical orientation of the site was analyzed on significant days of the 260-day calendar, including lunar cycles and two solstices. The most frequently occurring orientations were dated between 1100 and 750 BC and were aligned with sunrises on February 11 and October 29 when placed side by side against Gregorian calendar . These two dates on cholq’ij they were separated from each other by a full 260 days. Another such sighting was the presence of the Venus star which coincides with the rainy season.
“From the first orientations we analyzed [that] reflect the use of this cycle are embedded in architectural complexes located along the southern coast of the Gulf of Mexico, this was most likely the area where the 260-day count originated,” says Šprajc.
The greatest strength of the new study lies in its large sample size, which supports further written evidence that timekeeping emerged during Formative period (1000 BC – 500 AD). All in all, the biggest contribution is the convincing evidence that the Mayan calendar had its origins long before the actual written one was attested.
Other cosmological arrangements and their specific orientations remain unresolved for now, but in the future these discoveries raise further questions about the practices of ancient Mesoamerican tribes. These structures also lie at the heart of community building and Mayan identity and open up even more possibilities!
Top image: Intricate Mesoamerican calendars have fascinated for centuries. New LiDar surveys provide evidence that they were used much earlier than previously thought. Source: Frente / Adobe Stock
By Sahir Pandey
The use of the ancient Mesoamerican calendar is much older than previously thought – study . 6 January 2023. Jerusalem Post. Available in: https://www.jpost.com/archaeology/article-726639
Bower, B. 6 Jan 2023. Lasers reveal sites used as America’s oldest known star calendars . Available in: https://www.sciencenews.org/article/laser-americas-olmec-maya-star-calendar.
Handwerk, B. 6 January 2023. Mesoamericans have used a 260-day ceremonial calendar for millennia . Available in: https://www.smithsonianmag.com/science-nature/earliest-evidence-of-260-day-calendar-use-found-in-mexico-180981399/.
Ortega, RP January 6, 2023. Mayan calendar may be more than 3,000 years old, laser mapping reveals . Available in: https://www.science.org/content/article/maya-calendar-may-be-more-3000-years-old-laser-mapping-reveals.
Sprajc, I. et al . 2023. The Origins of Mesoamerican Astronomy and the Calendar: Evidence from the Olmec and Maya Regions . Science Advances, 9(1). Available in: DOI: 10.1126/sciadv.abq7675 .