High Quality Content by WIKIPEDIA articles! Mesoamerican calendars are the calendrical systems devised and used by the pre-Columbian cultures of Mesoamerica. In addition to the basic function of a calendar—defining and organizing periods of time in a way that allows events to be fixed, ordered and noted relative to each other and some absolute progression—Mesoamerican calendars were also used in religious observances and social rituals, such as for divination.