Oldest Calendar

The revelation of the oldest calendar is based on a comprehensive review of data from an archaeological site in northern Scotland— a series of ancient pits that researchers believe to be the oldest calendar in the world. It is about five thousand years older than its nearest rival, a Bronze Age Mesopotamian calendar.

Archaeologists think that Stone Age Britons created the network of pits around 10,000 years ago to reflect the months of the year and the lunar phases of the month. They think it also allowed for the observation of the midwinter sunrise – essentially the beginning of a new year – so that the lunar calendar could be re-calibrated annually to align it with the solar year.

Remarkably, the monument was used for almost 4,000 years, from approximately 8,000 BC (early Mesolithic) until about 4,000 BC (the early Neolithic).

Throughout four millennia, the pits frequently re-dug dozens or hundreds of times. Therefore, it is hard to determine whether they initially supported wooden pillars or standing stones after they were dug 10,000 years ago. Nonetheless, differences in the depths of the pits indicate that the arc had a sophisticated design, with each lunar month possibly split into three roughly ten-day ‘weeks’ symbolizing the waxing moon, gibbous/full moon, and decreasing moon.

The 50-meter-long row of twelve major holes was set in an arc facing a v-shaped depression in the horizon from where the sun emerged on a midwinter’s day. There are 12.37 lunar cycles (lunar months) in a solar year, and archaeologists assume that each pit represents a particular lunar month, with the complete arc symbolizing an entire year.

The 12 pits may have also served as a representation of the lunar month. The succession of holes, arranged in a shallow arc (perhaps symbolizing the moon’s movement across the sky), begins small and shallow at one end, grows in diameter and depth towards the middle of the arc, and then diminishes in size at the other end, thus emulating the waxing and waning of the moon, which takes 29 and a half days.

In its function as an annual calendar (covering 12 months, one for each pit), a pattern of alternating pit depths suggests that adjacent months may have been paired in some way, possibly reflecting a dualistic cosmological belief system – known in the ethnographic and historical records of many parts of the world, but not previously detected archaeologically from the Stone Age.

The hunter-gatherer tribes of the Mesolithic would have benefited tremendously economically and spiritually from timekeeping. Their calendar would have enabled them to predict the exact moment that animal herds would likely migrate or the most likely time that salmon would begin to run.