365-day calendar 365-day calendar A 365-day calendar consists of exactly 365 days per year (no leap days), and is primarily used in computer models and as an assumption in every-day calculations. For example, a calculation of a daily rate may use an annual total divided by exactly 365. Interest rates in some banks are calculated using a 365-day calendar. Some Mesoamerican calendars used a 365-day year with no leap year, resulting in a gradual shift of the seasons relative to the calendar. This includes the Maya Haab' and the Aztec Xiuhpohualli calendars. Some versions of the Zoroastrian calendar also use a fixed
History of the Americas This civilization is considered the mother culture of the Mesoamerican civilizations. The Mesoamerican calendar, numeral system, writing, and much of the Mesoamerican pantheon seem to have begun with the Olmec. Some elements of agriculture seem to have been practiced in Mesoamerica quite early. The domestication of maize is thought to have begun around 7,500 to 12,000 years ago. The earliest record of lowland maize cultivation dates to around 5100 BC. Agriculture continued to be mixed with a hunting-gathering-fishing lifestyle until quite late compared to other regions, but by 2700 BC, Mesoamericans were relying on maize, and living mostly in villages.