Aztec civilization bore a rich culture which had centuries-long traditions of art and architecture. Over the course of Aztec Empire during the 14th, 15th, and early 16th centuries, Aztecs developed some remarkable works of art, sculpture, and architecture. One of the most important works of Aztec sculpture is the famous Aztec Sun Stone, also known as Aztec Calendar Stone or Stone of the Five Eras. It is generally considered the most famous work of Aztec sculpture and continues to provide important insight about the Aztec calculation of time.
The Aztec Sun Stone was carved in 1479 and was dedicated to the sun god. After the Spanish conquest of the Aztec Empire in 1521, the stone was buried in the Zocalo at the main square of the present-day Mexico City. The stone was rediscovered in 1790 during the renovation of the Mexico City Cathedral. The stone is a massive carving with 12 feet across and having a weight of about 25 tons. Basalt was the material used for making the Aztec Sun Stone. Basalt is a form of solidified lava which is commonly found in places where volcanoes are common.
Aztec Sun Stone is composed of a central disk and various rings followed by elaborate mechanism for the calculation of eras. On the central disk is the figure of the Aztec sun god, Tonatiuh. He was considered the sun god of the fifth and the final era. According to Aztec beliefs, four eras had passed before the present one and calculations for these eras are given on the Aztec Sun Stone. The central disk shows the sun god Tonatiuh holding a human heart in each hand and his tongue representing the sacrificial knife. This signified the need of sacrifice for the sun god and thus human sacrifice was part of the rituals offered to the sun god.
Around the central disk of Aztec sun stone bearing the figure of Aztec sun god Tonatiuh, there are four squares representing the four eras that have passed. According to Aztec beliefs, the world was destroyed at the end of each era and then recreated for the next era. The top right square shows 4 Jaguar which was the day on which the first era started. It ended after having lasted 676 years. According to the Aztec beliefs, its end was caused by monsters that devoured all humanity. The top left square shows at 4 Wind which was the last day of the second era. This era lasted for 364 years and was ended by destruction caused by hurricanes during which humans were converted into monkeys.
At the bottom left of the Aztec Sun Stone the square shows 4 Rain which, according to the Aztec beliefs, was the third era. This one lasted 312 years and was destroyed by a rain of fire during which humans were converted into turkeys. Finally, the bottom left square shows 4 Water which was the 4th era. This era had same number of years as the first era and lasted 676 years. This era ended as a result of a massive flood during which all the humans were converted into fish.
Followed by the squares representing the four eras on Aztec Calendar Stone, there are calculations for the two Aztec calendars: The Xiuhpohualli and the Tonalpohualli. Xiuhpohualli was the solar calendar which consisted of 18 months with 20 days each. Each month was divided into four 5-day weeks. Together, this made up 360 days with five days added as extra at the end, bringing the total count to 365. The 360-day period was known as ‘Xihuitl’ by the Aztecs while the five extra days were called “Nemontemi” which means “days of nothing”.
In addition to the solar calendar, there was a sacred calendar on Aztec Sun Stone. This calendar was called Tonalpohualli and was devised to keep track of religious ceremonies. This calendar was divided into 20 periods with each period having 13 days called trecenas. Additionally, this calendar also associated the heads of gods with each one of the trecenas in order to represent the days reserved for each god. Both the calendars coincided once after every 52 years and human sacrifice was offered at that time in the absence of which the Aztecs thought the world would face destruction.
The Aztec solar calendar on the Aztec Sun Stone associates each day with the image of an animal or something else that represented a particular god. Additionally, each day was also associated with one of the four cardinal directions. For instance, the day cipactli was associated with the image of a crocodile and the direction of east. Some other days and their images along with associated directions included calli associated with the symbol of house and west, coatl associated with snake and east, atl associated with water and east, mazatl associated with deer and west, acatl associated with reed and east, and others.
The 52-year cycle after which both the solar and the sacred calendars on Aztec Sun Stone coincided can be considered the Mesoamerican “century”. At the end of each such century, New Fire Ceremony was held. This was a grand religious festival lasting for 12 days. Fasting was undertaken as a symbol of penitence during this festival and city lights were extinguished at its start. On the 12th day of festival, human sacrifice was offered to the sun god. This was done in the customary manner by removing the heart of the victim.
The Aztec Calendar Stone was a remarkable work of architecture and geometry by the Aztecs and represented their way of calculating time. It consisted of a solar and a sacred calendar. The solar calendar was used to calculate the ordinary days and consisted of 365 days. The sacred calendar consisted of 260 days. Both these calendars coincided after every 52 years which formed one Mesoamerican century. At the end of every century, the New Fire Ceremony was held during which human sacrifice and other rituals were offered.