He also deciphered the Maya system for measuring time, now called the Calendar Round ... spent the previous year assigning Thompson's "T"-numbers to the city's inscriptions.

Despite the mysticism that often clouds the Mayan calendar in popular culture, fact remains that the calendar system in use by the Mayans was based on a system used throughout the pre-Columbian ...

The Mayan calendar’s 819-day cycle has confounded ... From there, though, we need to start extrapolating out the 819 number, and if you chart 20 cycles of 819, you can fit every key planet ...

since it rests on a great number of coincidences between recorded astronomical events in the Mayan and Gregorian calendars. "The Mayans invented their system about 613 B. C." Dr. Spinden said ...