Center part of the Aztec Calendar.
The Calendar and the Sun Stone
Mistakenly, one often refers to the Sun Stone, or the Stone of Axayacatl, as the Aztec Calendar. This sculpure does depict the 20 daysigns, and even the four era’s of Suns that preceeded the current Fifth Sun but is was not used as a calendar. Instead it was used as a sacrifical altar. So, what actually is the Aztec calendar?
Not just one calendar
There is not just one Aztec calendar, there are two more or less independent systems. One calendar, called the xiuhpohualli, has 365 days. It describes the days and rituals related to the seasons, and therefor might be called the agricultural year or the solar year. The other calendar has 260 days. In Nahuatl, the language of the Aztecs, it is called the tonalpohualli or, the day-count. Most information on this Internet-site refers to the tonalpohualli, which is the sacred calendar.
The tonalpohualli and Aztec cosmology
The tonalpohualli, or day-count, has been called a sacred calendar because its main purpose is that of a divinatory tool. It divides the days and rituals between the gods. For the Aztec mind this is extremely important. Without it the world would soon come to an end. According to Aztec cosmology, the universe is in a very delicate equilibrium. Opposing divine forces are competing for power. This equilibrium is in constant danger of being disrupted by shifting powers of the gods, of the elemental forces that influence our lifes. This struggle cannot be won by any god. The notion that everything ultimately consists of two opposing forces is essential to the Aztec worldview. The world is always on the brink of going under in a spiritual war, a war of gods competing for supreme power. To prevent this from happening, the gods have been given their own space, their own time, their own social groups, etcetera, to rule over. The tonalpohualli tells us how time is divided among the gods.
For more info, please go to http://www.azteccalendar.com