There have been many hypotheses surrounding Stonehenge and its long-lost origins. Can a mathematical assessment by Rootclaim help shed light on its original purpose?

The large prehistoric monument in rural England is comprised of a circle of upright stones. It was constructed around 5,000 years ago, under circumstances that have long been lost in the annals of history. Some believe that Stonehenge served a religious function, while others say it was used as a burial site or a place of mystical healing. Yet others argue that it served as a giant calendar. There are also conflicting claims about how the bluestones used to build Stonehenge were moved from their place of origin 150 miles away. One explanation is that a glacier flow moved the stones, while another view says that people transported them from quarries in Preseli.

How can probability theory help?

Probability theory helps researchers measure uncertainty. And there’s plenty of uncertainty surrounding Stonehenge. By using a probabilistic framework, we can model the likelihood of each piece of evidence relating to Stonehenge.

Take the design: the alignment of the structure with the sunrise/sunset of the winter and summer solstices is reasonable if the goal was a calendar or sun worship. Various points on the perimeter of the circle align with the movements of the sun and moon. This is relatively understandable if the monument itself is related to the sun (sun worship or a calendar). However, if Stonehenge was only intended for burials or healing, then such an alignment would be much less likely.

Additional support comes from what archaeologists have found in and around Stonehenge. Bones from different parts of England indicate that a large number of young animals were killed there. The age of the animals at their time of death, coupled with the fact that most large animals are born in the spring, seems to correspond with the winter solstice. This is yet another piece of evidence supporting the calendar or sun worship hypotheses. It is a bit more likely if Stonehenge was intended for worship, since the animals may have been offered as sacrifices.


Rootclaim analyses examine each piece of evidence and assess the likelihoods given each potential hypothesis. The final numbers are entered into a Bayesian network, which calculates the final probabilities.

In this case, Rootclaim examined more than 25 pieces of evidence before calculating that the most likely explanation is that Stonehenge was built for sun worship, using stones that had been transported via glacial flow.

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