The Aztec calendar is a complex system that actually utilizes two different systems. One Aztec calendar is called the xiuhpohualli, which has 365 days. This calendar displays a variety of information important to the Aztec Indians. For example, it is used to describe the days and rituals as they relate to the seasons. Since this Aztec calendar is driven primarily by the changing of the seasons, it is said to represent the solar year or the agricultural year.
The other calendar is called the tonalpohualli, which has 260 days. This calendar, also referred to as “day-count,” is considered to be the sacred Aztec calendar. This is because it divides the days and rituals among the gods. This is extremely important in the Aztec culture because the calendar helps ensure a balance of time amongst the gods. According to the Aztec religion, it is necessary to divide time equally among the gods in order to maintain balance. Without a balance among the gods, a spiritual war would ensue and bring an end to the world.
Circular Aztec Calendar
The Tonalpoualli Aztec calendar is made of two interconnecting wheels. One wheel contains the numbers 1-13. The second wheel contains twenty different symbols. Combining the number one with the first of these symbols creates the first day on this Aztec calendar. Combining the number 2 with the second symbol creates the second day on the calendar. After thirteen days have passed, the first week is complete. The first wheel then returns to the number one, but the wheel with the symbols continues on to the fourteenth symbol. At the end of 260 days, both wheels have completed their rotations and return to their original position. The entire process then starts over again.
Aztec Calendar National Museum of Anthropology and History © Michael McCarty
By using this specialized Aztec calendar, the Aztecs were able to divvy up days among 20 of their gods. Each day devoted to a particular god was referred to as a dayssign. For example, day 3 was dayssign Calli and was dedicated to the god Tepeyollotl. Because this Aztec calendar was divided into 13-day weeks for a total of 260 days, one week of the year was also dedicated to a specific god. For example, the 17 th week of the year was Atl and was dedicated to the god Chalchihuihtotlin. Because of the importance of the Aztec calendar to the culture and religion of the Aztec people, the Aztec calendar stone is one of the most famous symbols of Mexico today.