Two mural fragments excavated at San Bartolo in Guatemala that evince the earliest known Mayan calendar record (photograph by Karl Taube; all images courtesy Proyecto Regional Arqueológico San Bartolo-Xultun)

Archaeologists excavating a Mayan site in San Bartolo, Guatemala have discovered what they believe to be the oldest calendar notation from the region, which they date to between 300 and 200 BCE. Known for its mural paintings from the Late Preclassic period (400 BCE to 100 CE), San Bartolo contains a pyramid and auxiliary several buildings in an archaeological complex called Las Pinturas.

San Bartolo is also the site where the earliest Mayan inscriptions were first found in 2006, by many of the same researchers as those involved in this most recent discovery. 

Reconstruction of “Sub-V phase” architectural complex at San Bartolo (illustration by Heather Hurst)

During the Late Preclassic period, much of the writing and art was done with paint on lime plaster surfaces. As outlined in an article published last week in the journal Science Advances, the researchers deciphered hieroglyphic script depicted on two adjoined mural fragments; one inscription, the calendar symbol for “7 Deer,” was represented by a dot on top of a bar and a line drawing of a head of a deer. The 260-day calendar, which was used throughout ancient Mesoamerica and continues to be used by certain Indigenous communities in southern Mexico and Guatemala, marked days by a combination of a number from one to 13 and one of 20 named days such as “rabbit,” “grass,” “monkey,” “water,” or in this case, “deer.”

Researchers speculate that “7 Deer” refers to either a year or the name of a historical figure or deity. The Maya had three other calendars in addition to this religious divination calendar called the Tzolk’in, including a solar calendar, a lunar calendar, and the Long Count calendar which monitored longer time cycles. 

Detail of fragment collected from Las Pinturas with “7 Deer” day sign and two hieroglyphic signs in a vertical column (photograph by Heather Hurst, illustration by David Stuart)

They were able to pin down the date of the fragments to a 100-year interval in the first millennium BCE through radiocarbon dating of organic material found close to where the fragments were unearthed. The oldest artifacts were found at the heart of the Las Pinturas site, with similarly aged items lying in close proximity to each other. The fragments were found in a complex that housed a pyramid, a ballcourt, and a long platform; painted murals and lime plaster etched with symbols are thought to have decorated the site.

Piecing together the fragments was a huge task in itself: About 7,000 fragments from several murals were collected between 2002 to 2012, and 11 were dated.

Illustration of the day sign with annotations (illustration by David Stuart)

This discovery confirms that the 260-day calendar has been in use for at least 23 centuries, though researchers are confident that the calendar had already been well established by the time “7 Deer” was carved into the fragments. That’s because the fragments attest to the work of several scribes with different writing styles, evincing a “robust scribal tradition,” according to the study.

Researchers also suggest that this find destabilizes theories that attempt to ascribe the origin of Mesoamerican writing to one geographic location such as Oaxaca.

“The 260-day calendar has long been a key element in the traditional definitions of Mesoamerica as a cultural region, and its persistence in many communities up to the present day stands as a testament of its importance in religious and social life,” the study says. “Our ability to trace its early use back some 23 centuries stands as another testament to its historical and cultural significance.”

Jasmine Liu is a former staff writer for Hyperallergic. Originally from the San Francisco Bay Area, she studied anthropology and mathematics at Stanford University.