Tōnalpōhualli

The tōnalpōhualli (often rendered without macrons as tonalpohualli) is the 260‑day ritual calendar used by several Mesoamerican civilizations, most prominently the Aztec (Mexica) and the Maya. The name derives from Nahuatl: tōnal “day” and pōhualli “count” or “cycle,” literally “day count.”

Structure

• Length: 260 days, formed by the interlocking of two cycles:
  1. Numbers 1–13 (a trecena cycle)
  2. Twenty day‑names (called tonalpohualli day signs)
• Each day is identified by a combination of a number (1‑13) and one of the twenty day‑names, producing 260 unique day designations before the pattern repeats.
• The twenty day‑names include Cipactli (Crocodile), Ehecatl (Wind), Calli (House), Cuetzpalin (Lizard), Coatl (Serpent), among others.

Function and Context

• Ritual and divination: The tōnalpōhualli was primarily employed for determining auspicious dates for religious ceremonies, planting, warfare, and personal destinies. Priests and diviners consulted the calendar to interpret omens associated with each day‑sign and number.
• Complement to the solar calendar: It ran concurrently with the xiuhpōhualli, the 365‑day solar calendar. The two calendars intersected in a 52‑year cycle known as the calendar round, after which the same combination of tōnalpōhualli and xiuhpōhualli dates recurred.
• Iconography: Codices such as the Codex Borbonicus and the Florentine Codex illustrate the day‑names and their associated deities, symbols, and ritual activities.

Historical Use

• Evidence of the 260‑day count appears in early Post‑Classic Mesoamerican sites (e.g., Teotihuacan, though the precise nature of its calendar there is debated) and is well documented among the Aztec and Maya of the 14th–16th centuries.
• Spanish chroniclers, including Bernardino de Sahagún, recorded the use of the tōnalpōhualli in Nahua societies during the early colonial period.

Scholarly References

• Clifford, T., & Tourtellot, R. (1978). The Calendar of the Aztecs. University of Oklahoma Press.
• Miller, M., & Taube, K. (1993). The Gods and Symbols of Ancient Mexico and the Maya. Thames & Hudson.
• Sahagún, B. de. (1568). Florentine Codex (Book XII: The Calendar).

The tōnalpōhualli remains a central subject of study in Mesoamerican archaeology, ethnohistory, and comparative calendrical systems.