The Mexica calendar round, called the xiuhmolpilli in Nahuatl, 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 calendar round was produced by the interlocking of the two cycles of the Mexica calendar system: the Tonalpohualli of 260 days and the Xiuhpohualli of 365 days. The two cycles ran in parallel, and they produced a unique combination every 52 years.
The Interlocking of the Two Cycles
The Tonalpohualli and the Xiuhpohualli were the two cycles of the Mexica calendar, and they ran in parallel throughout the year. The Tonalpohualli was a 260-day cycle that was used for divination and for the timing of religious rituals, and the Xiuhpohualli was a 365-day cycle that was used for the regulation of the agricultural year. The two cycles were not synchronized in the way that we think of the modern calendar, and they did not begin on the same day.
The two cycles produced a unique combination every 52 years, which was the period of the calendar round. The calculation of this period is relatively simple: 260 and 365 have a least common multiple of 18,980, which is 52 times 365 (or 73 times 260). After 52 years, the two cycles returned to their starting positions, and the same combination of day sign and month occurred again.
The Significance of the Calendar Round
The calendar round was the most important cycle in Mexica life, and it was the basis of the Mexica understanding of historical time. The Mexica believed that the calendar round was a complete cycle of time, and that the completion of a calendar round marked a moment of cosmic significance. The completion of a calendar round was a time for the renewal of the cosmic order, and it was marked by the New Fire Ceremony.
The Mexica also used the calendar round to record historical events. The events of the Mexica history were typically recorded with the day sign and the month of the event, and the events could be located precisely within the 52-year cycle. The system was sophisticated, and it allowed the Mexica to keep accurate records of their history over many generations.
The New Fire Ceremony
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 New Fire Ceremony was the most solemn and important of all Mexica rituals, and it was performed at the sacred hill outside Tenochtitlan called the Hill of the Star. The Mexica priests would wait for the rising of the Pleiades, the constellation that marked the beginning of the new cosmic age. If the Pleiades rose in the right position, the priests would light the new fire and the cosmos would be renewed. If the Pleiades did not rise, the Mexica believed that the end of the world had come.
The Survival of the Calendar Round
The calendar round was an important part of the Mexica calendar system. The Mexica system has been compared to similar systems in other pre-modern states, including the Maya calendar system and the Egyptian calendar system. The Mexica system is particularly notable for its sophistication and for its integration of the religious, agricultural, and historical cycles.
The Spanish conquest brought the Mexica calendar system to an end, and the Spanish imposed their own Gregorian calendar on the indigenous population. Yet many elements of the Mexica calendar have survived in the modern Mexican culture, particularly in the indigenous communities, where the traditional calendar continues to be used for agricultural and ritual purposes. The persistence of the Mexica calendar in the face of intense Spanish pressure ranks among the great survivals of Mexican culture.
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- The Aztec Calendar and Timekeeping — the broader context
- What is the Tonalpohualli, the 260-day calendar? — the ritual calendar
- What is the Xiuhpohualli, the 365-day calendar? — the solar calendar
- Aztec Rituals, Festivals, and Ceremonies — the religious uses
- Aztec Creation Myth and the Five Suns — the cosmic context
- Aztec Art, Architecture, and Science — the broader context