Piedra del Sol (1250/1500) by unknownMuseo Nacional de Antropología, México
'Piedra del Sol' was discovered in December 1790 during works on the Plaza Mayor. Miscalled the 'Aztec Calendar', it symbolizes the conception of time for the Mexicas, despite not actually working as a calendar.
In the center, there is an image of the Fifth Sun (Nahui Olin or Four Movement) and the face of Tonatiuh (god of the Sun). This particular representation has only the lower half of the face fleshless and the upper part normal, which symbolizes life and death.
In each of the corners of the sign is the name of the four suns...
Nahui Océlotl (Four Jaguar)
Nahui Atl (Four Waters)
Nahui Quiáhuitl (Four Rain)
Nahui Ehécatl (Four Wind)
According to the Nahua mythology of the Postclassic period, the world, as we know it nowadays, has gone through different eras of creation and destruction. They reference each of them with a particular sun.
The rest of the iconographic elements that decorate the Sun Stone are distributed in circles. Around the center there are the 20 signs of the days, which combined with the 13 numerals, formed a cycle of 260 days (also called Tonalpohualli).