Mesoamerican Long Count calendar Mesoamerican Long Count calendar The Mesoamerican Long Count calendar is a non-repeating, vigesimal (base-20) and base-18 calendar used by several pre-Columbian Mesoamerican cultures, most notably the Maya. For this reason, it is often known as the Maya (or Mayan) Long Count calendar. Using a modified vigesimal tally, the Long Count calendar identifies a day by counting the number of days passed since a mythical creation date that corresponds to August 11, 3114 BCE in the Proleptic Gregorian calendar. The Long Count calendar was widely used on monuments. The two most widely used calendars in pre-Columbian Mesoamerica, were the 260-day Tzolk'in
Mesoamerican calendars (year count) and "tonalpohualli" (day count) respectively. The Veintena was called "metztli" (moon), and the five unlucky days at the end of the solar year were called "nemontemi". Other calendar cycles were also recorded, such as a lunar calendar, as well as the cycles of other astronomical objects, most importantly Venus. Mesoamerican calendars Mesoamerican calendars are the calendrical systems devised and used by the pre-Columbian cultures of Mesoamerica. Besides keeping time, Mesoamerican calendars were also used in religious observances and social rituals, such as for divination. The existence of Mesoamerican calendars is known as early as ca. 500 BCE, with