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The Ancient Future: Mesoamerican and Andean Timekeeping

The Aztec, Maya, and Inca civilizations used complex and multiple timekeeping systems for purposes of agriculture, worship, and political authority. This exhibition shares information on the calendars of each of these cultures.


Plate II
Plate II: Aztec calendar stone. From Antonio de León y Gama, Descripción histórica y cronológica de las dos piedras . . ., 1832.

A 260-day calendar was used as a divinatory almanac throughout Mesoamerica, consisting of an internal structure of twenty day-names combined with thirteen day-numbers. This ritual calendar was used in conjunction with a solar calendar of 365 days, a recording of the seasonal year and important for agriculture. When these three reckoning systems are combined (imagine interlocking teeth in three distinct gears) they produce a total cycle of 18,980 uniquely named days, or fifty-two years.

Both the Aztecs and the Maya recorded time by cycle-building, accumulating little cycles to produce bigger cycles. The fifty-two-year cycle, known as the Calendar Round, was useful for recording recent and continuing events. Because the Calendar Round repeats the same cycle every fifty-two years, it is not effective for a longer view of time. To create unique dates, Mesoamericans  developed a third calendar system, one we call the Long Count. The Long Count begins on August 12, 3114 BCE and counts forward one place for each year.


Palacio del primer Inca en la isla del Sol
Palace of the first Inca on the Island of the Sun on Lake Titicaca. From Arthur Posnansky, Guía general, 1912.

Sun worship was the most important aspect of Inca religion. The Inca kept time by using solar markers, including stone towers built on hilltops, as well as the landscape features themselves. The sun towers are described by the chroniclers as being built in pairs and were used to mark off a block of time in the Inca calendar.  Marking the summer and winter solstices was an important part of Inca religion.

The Inca calendar consisted of twelve lunar months, with the year beginning in December. Throughout the year, the nobility and religious leaders celebrated each month with specialized public rituals and elaborate ceremonies to mark the phases of the agricultural cycle. Among the greatest festivals were those that marked the solstices, the maize harvest, and the beginning of the rainy season.


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