The Ancient Future: Mesoamerican and Andean Timekeeping
A 260-day calendar was used as a divinatory almanac throughout Mesoamerica, consisting of an internal structure of 20 day names combined with 13 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 52 years.
Both the Aztecs and the Maya recorded time by cycle-building, accumulating little cycles to produce bigger cycles. The 52-year cycle, known as the Calendar Round, was useful for recording recent and continuing events. Because the Calendar Round repeats the same cycle every 52 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.
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.