Aztec Sun Calendar

Timeline

1. c. -600–1300Mesoamerican civilization core area · MexicoThe Mesoamerican 260-day sacred calendar (tonalpohualli) and 365-day solar calendar traditions trace back to the first centuries BCE: the earliest known calendrical written record appears at the Zapotec site of Monte Albán (c. 6th century BCE), and recent archaeoastronomical research has also found traces of earlier 260-day counting in the Olmec cultural area. They were later continuously evolved and transmitted by the Maya, Toltec, and other civilizations. The Mexica (ancestors of the Aztecs) inherited and integrated this composite calendar system after migrating south to settle the Mexican Plateau, incorporating it into state religion and sacrificial institutions.
2. c. 1325–1430Tenochtitlan · Mexican PlateauAfter the Mexica founded Tenochtitlan on an island in Lake Texcoco, the calendar became a core tool of city-state governance: the 365-day solar calendar's 18 months (of 20 days each) plus 5 unlucky days corresponded to 18 agricultural and religious festivals, regulating the timing of sacrifice, sowing, war, and administration; the 260-day sacred calendar was used for divination, naming newborns, and predicting fortune and misfortune.
3. 1440–1469Tenochtitlan · Mexican PlateauUnder Moctezuma I (Moctezuma Ilhuicamina), the Aztec Triple Alliance empire expanded greatly, and the calendar was deeply integrated with the Flower Wars (Xochiyaoyotl) institution: specific calendar dates were regarded as sacred times for war to capture sacrificial victims, turning the solar calendar's cosmological order into a legitimizing basis for imperial political violence.
4. 1455Huixachtlan (Cerro de la Estrella) · Mexican PlateauThe New Fire ceremony was traditionally held in the year 2 Reed (Ome Acatl), not 1 Rabbit. 1454 was the year 1 Rabbit, and sources mostly record a great famine; 1455 was the year 2 Reed, the year of that calendar round's renewal. Priests extinguished the old fire and drilled new fire at Huixachtlan, symbolizing the sun's continued course. The original 'Ucocztan Chichutli' was a miswritten place name, corrected to Huixachtlan / Cerro de la Estrella.
5. 1455–1479Templo Mayor, Tenochtitlan · Mexico CityIn the new 52-year cycle opened after the 1454 New Fire ceremony, Aztec religious thinkers continued to deepen the pictorial expression of the Five Suns myth and the calendar system, accumulating the cosmological core for the famous Piedra del Sol (Sun Stone) carved near the Templo Mayor around 1479. The Sun Stone is about 3.6 meters in diameter and weighs about 24.5 tons, with the face of the sun god at its center and four preceding eras and day-sign symbols radiating outward; it is the most representative material remains of Aztec calendar culture.