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 writing systems skin covered with stucco. These codices are read in boustrophedon, a zigzag style in which the reader follows red lines that indicate the way to read. Most of the current knowledge about the writing of the Mixtecans is due to the work of Alfonso Caso, who undertook the task of deciphering the code based on a set of pre-Columbian and colonial documents of the Mixtec culture. Although the Mixtecs had a set of symbols that allowed them to record historical dates, they did not use the long count calendar characteristic of other southeast Mesoamerican writing systems. Instead, the codices that