Mesoamerican calendars prognostic power for the coming year. Therefore, People tried to do as little as possible on these days, and a person who was born during the nemontemi was considered unlucky. Since both the 260-day and the 365-day calendar repeat, approximately every 52 years they reach a common end, and a new Calendar Round begins. This 52-year cycle was the most important for most Mesoamericans, with the apparent exception of the Maya elite until the end of the Classic Era, who gave equal importance to the Mesoamerican Long Count calendar. According to their mythology, at the end of one of these
Mesoamerican Long Count calendar the GMT correlation is historical, astronomical and archaeological: Historical: Calendar Round dates with a corresponding Julian date are recorded in Diego de Landa's "Relación de las cosas de Yucatán" (written circa 1566), the Chronicle of Oxcutzkab and the books of Chilam Balam. De Landa records a date that is a Tun ending in the Short Count. Oxkutzcab contains 12 Tun endings. Bricker and Bricker find that only the GMT correlation in consistent with these dates. The Book of Chilam Balam of Chumayel contains the only colonial reference to classic long-count dates. The Julian calendar date of 11.16.0.0.0 confirms the GMT