Evidence indicates that the first calendar was created by the Stone Age people in Britain about 10,000 years ago. The earliest known calendar was a lunar calendar, which tracked the cycles of the moon.
According to National Public Radio, the first calendar consisted of 12 pits with large rocks that mimicked the lunar cycles. The creators of the calendar were hunter-gatherers who used the calendar to keep abreast of when certain animals migrated from one area to another or when certain species of fish spawned. Scientists also believe that the calendar makers used their creation to predict events such as eclipses.