The Aztec Calendar Stone - Not a Calendar After All

What Was the Purpose of the Aztec "Calendar Stone"?

Sun Stone or Aztec Calendar Stone, found in Tenochtitlan in 1789, Mexico, Azteca Civilization, 15th century
Sun Stone or Aztec Calendar Stone, found in Tenochtitlan in 1789, Mexico, Azteca Civilization, 15th century. De Agostini / G. Sioen / Getty Images

The Aztec Calendar Stone, better known in the archaeological community as the Aztec Sun Stone, is an enormous basalt disk covered with hieroglyphic carvings of calendar signs and other images referring to the Aztec creation myth. The stone, currently on display at the National Museum of Anthropology in Mexico City, measures about 3.6 meters (11.8 feet) in diameter, is about 1.2 m (3.9 ft) thick, and weighs more than 21,000 kilograms (58,000 pounds or 24 tons).

Aztec Sun Stone Origins and Religious Meaning

The so-called Aztec Calendar Stone was not a calendar, but most likely a ceremonial container or altar linked to the Aztec sun god, Tonatiuh, and festivities dedicated to him. At its center is the image of the god Tonatiuh, within the sign Ollin, which means movement and represents the last of the Aztec cosmological eras, the Fifth Sun.

Tonatiuh's hands are depicted as claws holding a human heart, and his tongue is represented by a flint or obsidian knife, which indicates that a sacrifice was required so that the sun would continue its movement in the sky. At Tonatiuh's sides are four boxes with the symbols of the preceding eras, or suns, along with the four directional signs.

Tonatiuh's image is surrounded by a broad band or ring containing a calendar and cosmological symbols. This ring contains the signs of the 20 days of the Aztec sacred calendar, called Tonalpohualli, which, combined with 13 numbers, made up the sacred 260-day year.

A second outer ring has a set of boxes each containing five dots, representing the five-day Aztec week, as well as triangular signs probably representing sun rays. Finally, the sides of the disk are carved with two fire serpents which transport the sun god in his daily passage through the sky.

Aztec Sun Stone Political Meaning

A sign representing the date 13 Acatl, 13 Reed, is visible on the surface of the stone.

This date corresponds to the year 1479 AD, probably the year in which the sculpture was completed. The political message for those who saw the stone was clear: this was an important year of rebirth for the Aztec empire, and the emperor's right to rule comes directly from the Sun god and is embedded with the sacred power of time, directionality, and sacrifice.

History of the Aztec Sun Stone

Scholars surmise that the basalt was quarried somewhere in the southern basin of Mexico, at least 18-22 kilometers (10-12 miles) south of Tenochtitlan, probably during the reign of Axayacatl [ruled 1469-1481]. After its carving, the stone must have been located in the ceremonial precinct of Tenochtitlán, laid horizontally and likely near where ritual human sacrifices took place. Scholars suggest that it may have been used as an eagle vessel--a repository for human hearts (quauhxicalli), or as a base for the final sacrifice of a gladiatorial combatant (temalacatl).

After the conquest, the Spanish moved the stone a few hundred meters south of the precinct, in a position facing upward and near the Templo Mayor and the Viceregal Palace. Sometime between 1551-1572, the religious officials in Mexico City decided the image was a bad influence on their citizens, and the stone was buried facing down, hidden within the sacred precinct of Mexico-Tenochtitlan.


The Sun Stone was rediscovered in December of 1790, by workmen who conducted leveling and repaving work on Mexico City's zocalo. The stone was pulled to a vertical position, where it was first examined by archaeologists. It stayed there for six months exposed to the weather, until June of 1792, when it was moved into the cathedral. In 1885, the disk was moved to the early Museo Nacional, where it held in the monolithic gallery--that journey was said to have required 15 days and 600 pesos.

In 1964 it was transferred to the new Museo Nacional de Anthropologia in Chapultepec Park, that journey only taking 1 hour 15 minutes. Today it is displayed on the ground floor of the National Museum of Anthropology, in Mexico City, within the Aztec/Mexica exhibition room.


Edited and updated by K. Kris Hirst

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