New finds about the stone circle's history, along with analysis of other ancient calendar systems, prompted professor Timothy Darvill to take a fresh look at Stonehenge. His analysis, published in the journal Antiquity, concluded that the site was designed as a solar calendar.

"The clear solstitial alignment of Stonehenge has prompted people to suggest that the site included some kind of calendar since the antiquarian William Stukeley," said Darvill, from Bournemouth University, "Now, discoveries brought the issue into sharper focus and indicate the site was a calendar based on a tropical solar year of 365.25 days."

Crucially, recent research had shown that Stonehenge's sarsens were added during the same phase of construction around 2500 BC. They were sourced from the same area and subsequently remained in the same formation. This indicates they worked as a single unit.

As such, Darvill analyzed these stones, examining their numerology and comparing them to other known calendars from this period. He identified a solar calendar in their layout, suggesting they served as a physical representation of the year that helped the ancient inhabitants of Wiltshire keep track of the days, weeks, and months.