Celtic calendar

The Celts did not appropriate the calendar from other peoples, but invented their own. The Celtic calendar is a compilation of pre-Christian Celtic systems of timekeeping. This calendar was used by the Celtic countries to define the beginning and length of days, weeks, months, seasons, quarter days and determine the timing of festivals.

The astronomical format of the Celtic calendar originated approximately around 800 B.C. Some calendars achieved complex synchronization of the solar and lunar months.

In Celtic culture, trees play a large role in astrology. As with the star signs, the tree calendar spans across different months and is aligned to the cycles of the moon. The Celtic Tree Calendar is a calendar with 13 lunar divisions. Each lunar month is ruled by a tree. This is also tied in with the old Ogham alphabet with each tree having a corresponding letter. Each theme in the Celtic tree months is strongly associated with Celtic culture and mythology.

Although there are various theories among historians, it is most likely that the tree system existed, with minor regional variations, before the time of the Druids who experimented with it, discovered the magical properties of each tree, and encoded all the information into the system.