The calendrical systems devised and used by the pre-Columbian cultures of Mesoamerica, primarily a 260-day year, were used in religious observances and social rituals, such as divination.
These calendars have been dated to early as ca. 1100 BCE. By 500 BCE at the latest, the essentials were fully defined and functional. 260-day calendars are still used in the Guatemalan highlands, Veracruz, Oaxaca and Chiapas, Mexico.
The history of science covers the development of science from ancient times to the present. It encompasses all three major branches of science: natural, social, and formal. Protoscience, early sciences, and natural philosophies such as alchemy and astrology that existed during the Bronze Age, Iron Age, classical antiquity and the Middle Ages, declined during the early modern period after the establishment of formal disciplines of science in the Age of Enlightenment.
The earliest roots of scientific thinking and practice can be traced to Ancient Egypt and Mesopotamia during the 3rd and 2nd millennia BCE. These civilizations' contributions to mathematics, astronomy, and medicine influenced later Greek natural philosophy of classical antiquity, wherein formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Latin-speaking Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but continued to thrive in the Greek-speaking Byzantine Empire. Aided by translations of Greek texts, the Hellenistic worldview was preserved and absorbed into the Arabic-speaking Muslim world during the Islamic Golden Age. The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived the learning of natural philosophy in the West. Traditions of early science were also developed in ancient India and separately in ancient China, the Chinese model having influenced Vietnam, Korea and Japan before Western exploration. Among the Pre-Columbian peoples of Mesoamerica, the Zapotec civilization established their first known traditions of astronomy and mathematics for producing calendars, followed by other civilizations such as the Maya.
The Aztec or Mexica calendar is the calendrical system used by the Aztecs as well as other Pre-Columbian peoples of central Mexico. It is one of the Mesoamerican calendars, sharing the basic structure of calendars from throughout the region.
The Aztec sun stone, often erroneously called the calendar stone, is on display at the National Museum of Anthropology in Mexico City.The actual Aztec calendar consists of a 365-day calendar cycle called xiuhpÅhualli (year count), and a 260-day ritual cycle called tÅnalpÅhualli (day count). These two cycles together form a 52-year "century", sometimes called the "calendar round". The xiuhpÅhualli is considered to be the agricultural calendar, since it is based on the sun, and the tÅnalpÅhualli is considered to be the sacred calendar.