Abstract:

Mesoamerican calendars were many and complex. There have been a good number of studies done to decipher them. By the arrival of Hernan Cortes in 1519 in what current day Mexico is, there were 21 calendars in use while 4 of them were extinct. Using astronomical observations, the Maya developed an elaborate system of calendars, among them the Tzolkin Calendar, the Haab Calendar, the Round Calendar and the Long Count. Which operations did the Maya use to perform their calendrical computations? While they used a vigesimal system to write the numbers, this system was never used in connection with days. No inscriptions use vigesimal numbers but rather quasi-vigesimal numbers. They also needed to divide to do some of the calendar conversions. I’ll illustrate calendrical computation within and among calendars and conversion examples in which division is needed.