# Calendars

A calendar is an agreement about how to count days against the sky. Some follow the Moon, some the Sun, many try to follow both, and each needs small repairs: leap days, leap months, skipped dates. Behind every one sits astronomy, arithmetic and a community that wants to meet on the same day.

Connects to:
- [Time](https://mapideas.org/i/time)
- [Day, month, year](https://mapideas.org/i/ti_daymonthyear)
- [The naked-eye sky](https://mapideas.org/i/as_sky)
- [Dating the past](https://mapideas.org/i/hi_dating)
- [How numbers travelled](https://mapideas.org/i/hi_numbers)
- [Zero](https://mapideas.org/i/mat_zero)
- [Archaeoastronomy](https://mapideas.org/i/as_archaeo)
- [Time as a cycle](https://mapideas.org/i/ti_cycles)
- [Why do we count in sevens?](https://mapideas.org/i/q_time_week)
- [Ritual and prayer](https://mapideas.org/i/re_ritual)

Sources:
- [Wikipedia: Calendar](https://en.wikipedia.org/wiki/Calendar)
- [Wikipedia: Gregorian calendar](https://en.wikipedia.org/wiki/Gregorian_calendar)

Source: https://mapideas.org/i/ti_calendars · open on the map: https://mapideas.org/#ti_calendars