The Mexica had one of the most sophisticated calendar systems of the pre-modern world, combining two interlocking cycles that together produced a 52-year calendar round. The first cycle, the Tonalpohualli, was a 260-day ritual calendar composed of 20 signs multiplied by 13 numbers. Each day in the Tonalpohualli had a unique combination of sign and number, and the calendar was used for divination, for the timing of religious rituals, and for the naming of children. The second cycle, the Xiuhpohualli, was a 365-day solar calendar composed of 18 months of 20 days each, plus 5 extra days at the end of the year. The Xiuhpohualli was used for the regulation of the agricultural year and for the timing of the great seasonal festivals.
The Tonalpohualli, the 260-Day Calendar
The Tonalpohualli was a ritual calendar that was used for divination, for the timing of religious rituals, and for the naming of children. The Tonalpohualli was composed of 20 signs, called tonalli, multiplied by 13 numbers, called ce. Each day in the Tonalpohualli had a unique combination of sign and number, and the calendar produced 260 days before the cycle was complete. The 260 days of the Tonalpohualli were divided into 20 periods of 13 days each, and each period was associated with one of the 20 signs.
The 20 signs of the Tonalpohualli were: cipactli (crocodile), ehecatl (wind), calli (house), cuetzpalin (lizard), coatl (serpent), miquiztli (death), mazatl (deer), tochtli (rabbit), atl (water), itzcuintli (dog), ozomatli (monkey), malinalli (grass), acatl (reed), ocelotl (jaguar), cuauhtli (eagle), cozcuauhtli (vulture), ollin (movement), tecpatl (flint), quiahuitl (rain), and xochitl (flower). Each sign had its own associations, its own deities, and its own fortune, and the day of one’s birth was believed to determine much of one’s destiny.
The Tonalpohualli was used by the priests, called tonalpouhqui, who were trained in the calmecac and who specialized in the reading of the calendar. The tonalpouhqui would consult the calendar to determine the auspicious days for various activities, including the planting of crops, the conduct of war, the performance of rituals, and the naming of children. The tonalpouhqui were also responsible for the preparation of the religious almanacs, called tonalpohualli or almanacs, which were used by the priests to determine the dates of the religious festivals.
The Xiuhpohualli, the 365-Day Calendar
The Xiuhpohualli was a solar calendar that was used for the regulation of the agricultural year and for the timing of the great seasonal festivals. The Xiuhpohualli was composed of 18 months, called veintenas, of 20 days each, plus 5 extra days at the end of the year, called the nemontemi. The 18 months of the Xiuhpohualli were, in order: Atlcahualo, Tlacaxipehualiztli, Tozoztontli, Huei Tozoztli, Toxcatl, Etzalcualiztli, Tecuilhuitl, Tlaxochimaco, Xochilhuitl, Atemoztli, Tititl, Izcalli, Yancuicilhuitl, Miccailhuitontli, Huey Miccailhuitl, Ochpaniztli, Teotleco, and Tepeilhuitl.
Each month of the Xiuhpohualli had its own festival, with its own rituals, its own sacrifices, and its own foods. The festivals were the principal public events of the year, and they were occasions for the entire community to participate in the religious life of the state. The most important festivals were those associated with the agricultural cycle, including the planting of maize, the growth of the maize, and the harvest of the maize.
The 5 extra days at the end of the year, the nemontemi, were considered to be unlucky, and the Mexica refrained from most activities during this period. The Mexica believed that the nemontemi were a dangerous time, and they performed a series of rituals to protect themselves from the evil influences that were believed to be active during this period. The nemontemi were also a time for the religious specialists to perform purification rituals and to prepare for the new year.
The Calendar Round
The two cycles of the Mexica calendar, the Tonalpohualli and the Xiuhpohualli, ran in parallel, and they produced a unique combination every 52 years. This period of 52 years was called the xiuhmolpilli, or “bundle of years,” and it was the basis of the Mexica understanding of historical time. The calendar round was the most important cycle in Mexica life, and it structured the religious calendar, the agricultural calendar, and the historical memory of the Mexica people.
The end of a calendar round was a moment of cosmic danger, and the closing of one round and the beginning of the next was marked by the New Fire Ceremony. In this ceremony, all fires in the Valley of Mexico were extinguished, the people waited in darkness, and the priests lit a new fire on the breast of a sacrificial victim. The new fire was then carried to every settlement in the valley, symbolically re-creating the cosmos and ensuring the continuation of the Fifth Sun.
The Astronomical Observations
The Mexica calendar system required sophisticated astronomical observations, and the Mexica were skilled astronomers who could predict eclipses and who kept careful records of the movements of the sun, the moon, and the planets. The Mexica had a special interest in the planet Venus, which was associated with Quetzalcoatl, and they kept careful records of its appearances and disappearances. The Mexica believed that the appearance of Venus as the morning star was a particularly dangerous time, and they postponed the most important rituals until the planet had moved to a safer position.
The Mexica also observed the Pleiades, the constellation that was associated with the New Fire Ceremony. The Mexica believed that the Pleiades would rise in a particular position at the end of each calendar round, and they used the position of the constellation to determine the exact moment for the lighting of the new fire. The Mexica also observed the solstices and the equinoxes, and they built a number of observatories in the Valley of Mexico to facilitate the astronomical observations.
The Mexica used a number of astronomical instruments, including the cross-staff, the gnomon, and the sighting tube. The cross-staff was used to measure the angle between two celestial objects, and the gnomon was used to determine the time of day by the shadow cast by a vertical stick. The sighting tube was used to observe the position of the stars and the planets. The Mexica were also skilled at the construction of aligned structures, and they built a number of temples and pyramids that were aligned with the solstices and the equinoxes.
The Survival of the Mexica Calendar
Many elements of the Mexica calendar survived the Spanish conquest and continued to influence Mexican culture for centuries. The Spanish recognized the sophistication of the Mexica calendar, and they attempted to suppress it. Yet the calendar continued to be used in many indigenous communities, where it remained central to the religious and agricultural life. The calendar was also incorporated into the folk Catholicism of the colonial period, and many of the Christian festivals were synchronized with the traditional Mexica festivals.
The modern Mexican calendar, while based on the European Gregorian calendar, retains many of the basic elements of the Mexica calendar. The day names, the month names, and the agricultural cycle are all derived from the Mexica tradition, and they continue to shape the rhythm of Mexican life. The Mexica calendar is also widely remembered in modern Mexico, and it is a popular subject in art, in literature, and in popular culture.
Related Articles
See also:
- What is the Tonalpohualli, the 260-day calendar? — the ritual calendar
- What is the Xiuhpohualli, the 365-day calendar? — the solar calendar
- How did the Aztec calendar round work? — the 52-year cycle
- Aztec Rituals, Festivals, and Ceremonies — the religious uses of the calendar
- Aztec Creation Myth and the Five Suns — the cosmic context
- Aztec Art, Architecture, and Science — the broader context