There are an endless number of theories as to the purpose of Stonehenge, the most famous stone circle in the world. While some are truly out there, the most commonly accepted possibilities usually revolve around some sort of time-keeping using the Sun, Moon and stars.
However, there has never been any consensus on which of those theories is correct – and now, another has been added to the list: that the megaliths themselves might have acted as a ‘count’ of the days and months of the year.
In the paper “Keeping Time at Stonehenge“, published this month in the prestigious journal Antiquity, English archaeologist Timothy Darvill describes how the famous megaliths might have acted as “a Late Neolithic solar calendar”. He notes that one of the few things that is agreed upon with Stonehenge is that the solstices (the times of the year when the Sun reaches its most northern and southern points on the horizon as it rises and sets) are embedded into the architecture of the monument, which “strongly suggests a solar-based system.”
With this in mind, Darvill noticed that the numbers of stones in different parts of the circle seemed to fit well with ancient systems of yearly time-keeping: the ‘Sarsen Circle’ has thirty uprights, the ‘Trilithon Horeshoe’ has five components, and there are four ‘Station Stones’.
“The core of the year is represented by the Sarsen Circle,” Darvill says. “Here, each of the 30 uprights represents a solar day within a repeating 30-day month. Twelve monthly cycles of 30 days, represented by the uprights of the Sarsen Circle, gives 360 solar days.”
Furthemore, he points out, moving around this circle from the main axis, there are anomalously sized stones at #11 and #21, suggesting perhaps that the 30 day month was divided into three ‘weeks’, or ‘decans’, of ten days each.
Notably, however, Darvill did not find a section of the monument that might be used to count through the 12 cycles of 30 day months – though he does suggest that “it is possible that the poorly known stone settings in and around the north-eastern entrance somehow marked this cycle.”
With the true solar year actually being fairly close to 365.25 days though, rather than 360 days, Darvill says that other sections of the Stonehenge site could have been used to keep the calendar accurate:
Completing the basic tropical year requires an additional five days: an intercalary month of days known in later calendars as epagomenal days. The five components of the Trilithon Horseshoe, situated prominently in the centre of the structure, fit this role… Adding the intercalary month gives 365 solar days. Making the solar calendar a perpetual one, in which the days, decans and months keep pace with the seasons and the movements of the sun to describe a tropical solar year with accuracy, requires periodic adjustment, specifically, the addition of one day every four years to create a leap-year of 366 solar days. The four Station Stones provide a means of keeping tally so that a sixth day could be added to the intercalary month every fourth year.
Furthermore, he says that “using the solstitial alignment ensures that the calendar was synchronised with celestial movements and the changing of the seasons.”
Ironically, though, this theory removes a lot of the puzzling about possible alignments found in many of the other theories about Stonehenge’s use (with so many stones, it’s very easy to make your theory fit if you draw enough lines). In Darvill’s theory, the solstice alignments are just there as checks and balances; the counting is done purely by using the stones, rather than alignments or shadows.
An Echo of Egypt?
Not content to rock the boat just with a new theory about how Stonehenge might work, Darvill then extends on his thoughts by suggesting that the knowledge to build such a calendar may have come from a far-away land. While he does acknowledge that “it is entirely possible that communities living in north-western Europe during the late fourth and third millennia BC developed a solar calendar of the type suggested here on their own initiative”, he also points out that “the uniqueness of Stonehenge…prompts a pause for thought”:
External influences may also be possible, especially given contemporaneous developments 3500km away in the Eastern Mediterranean. Here, during the fourth millennium BC, a variety of lunar-stellar calendars used observational astronomy to reconcile the movements of the moon and stars with the daily and seasonal cycles of the sun. During the early third millennium BC, however, increased interest in solar deities, such as the cult of Ra, led to the development in Egypt of a 365-day solar calendar, known as the Civil Calendar… Just as at Stonehenge, the calendar comprises twelve 30-day months, together with an intercalary month of five epagomenal days. The months are each divided into three weeks of 10 days. The need for an additional day every four years to keep track with the seasons was understood, although not implemented until much later.
Is it likely though that Ancient Egyptian calendar techniques would have been adopted by the people living far away in what is now southern England? Darvill references recent finds that are indicative of long-distance contact and trade at this remote time in history (around 4,500 years ago).
For instance, the so-called ‘Amesbury Archer’ was buried five kilometres south-east of Stonehenge around 2,300 BC with an array of grave goods that included some from continental Europe. Isotope analysis shows that he was born and raised in the Alps and moved to Britain as a teenager.
And Ancient Egypt is known to have engaged in long-distance trade well beyond its border during Early Dynastic times: stone vessels and scarabs were found at Minoan Crete. Amongst the earliest known imports to Britain is a large, red-glass bead from a barrow located 2.3km south-west of Stonehenge, which was probably made in Egypt in the early second millennium BC.
The new theory has received mixed reviews from Darvill’s peers:
This Stonehenge calendar system “makes a lot of sense,” says David Nash at the University of Brighton, UK. “I like the elegant simplicity of it.”
Others are not so sure. “It’s certainly intriguing but ultimately it fails to convince,” says Mike Parker Pearson of University College London, UK. “The numbers don’t really add up – why should two uprights of a trilithon equal one upright of the sarsen circle to represent 1 day? There’s selective use of evidence to try to make the numbers fit.”
[Sacha Stern, an expert in ancient calendars at University College London] is not convinced by the argument that the Stonehenge calendar system originated elsewhere. “I wonder if you need to invoke the Egyptians. Why can’t we just imagine that [the people who built Stonehenge] created the whole system by themselves? They certainly knew when the solstice was, and from that point onwards you just have to count the days, and it won’t take long to figure out how many days you need in the year.”
As with all things lost to history, it may be that we’ll never know exactly what Stonehenge was meant to be used for. But it’s always interesting to throw ideas out there and see if we can find corroborating evidence for them.
Paper: “Keeping Time at Stonehenge“