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
Year of three popes popes have held office in a given calendar year. Years in which the Roman Catholic Church was led by three different popes include: There was also a year in which the Roman Catholic Church was led by four popes, called the Year of Four Popes: Year of three popes A year of three popes is a common reference to a year when the College of Cardinals of the Catholic Church are required to elect two new popes within the same calendar year. Such a year generally occurs when a newly elected pope dies or resigns very early into his papacy.