A new study has revealed that the stone circle in Dorset, UK known as Flagstones monument is significantly older than previously believed, dating back to around 3,200 B.C. The discovery places it as the oldest known circular enclosure in Britain, predating the first phase of Stonehenge by at least 700 years.
The findings, published in the journal Antiquity, resulted from a collaborative research effort by the University of Exeter and Historic England. Using advanced radiocarbon testing, scientists analyzed 23 samples, including human bones, deer antlers, and charcoal, to confirm the monument’s age.
The Flagstones site was first uncovered in the 1980s during construction of the Dorchester bypass. Excavations revealed a massive circular ditch measuring approximately 100 meters in diameter, likely surrounded by an earthen bank.
Part of the site now lies beneath the bypass, while the rest is under Max Gate, the former home of writer Thomas Hardy, which the National Trust now manages.
Archaeologists also discovered human burials within the enclosure. The remains included a cremated adult and three uncremated children, as well as partial cremations of three other adults. A separate burial, dating about 1,000 years later, contained the skeleton of a young adult male beneath a large sarsen stone at the site’s center.
“Flagstones is an unusual monument; a perfectly circular ditched enclosure, with burials and cremations associated with it,” said Dr. Susan Greaney, a specialist in Neolithic and Bronze Age structures at the University of Exeter.
The new dating evidence suggests that Flagstones was built centuries before previously estimated. Researchers now believe the site underwent two phases of use: the first, around 3,650 B.C., involved early Neolithic activity such as pit digging, while the main circular ditch was constructed around 3,200 B.C.
This timeline challenges previous assumptions that linked Flagstones to the first phase of Stonehenge, which dates to approximately 2,900 B.C.
Some experts now suggest that Stonehenge could have been influenced by Flagstones, rather than the two sites being constructed in the same period.
“The ‘sister’ monument to Flagstones is Stonehenge, whose first phase is almost identical, but it dates to around 2900 BC.,” Greaney said. “Could Stonehenge have been a copy of Flagstones? Or do these findings suggest our current dating of Stonehenge might need revision?”
The study also highlights Flagstones’ connection to other Neolithic sites, including Llandygái ‘Henge’ A in Wales and locations in Ireland. Burial customs and artifacts found at the site suggest that prehistoric communities across Britain and beyond were more interconnected than previously thought.
This discovery reinforces the idea that Neolithic groups communicated, shared ideas, and perhaps even traveled between regions.
With its revised dating, Flagstones is now considered a key piece in understanding the evolution of ancient ceremonial structures in Britain. The findings raise new questions about the origins of large-scale monument building and the long-lasting influence of early Neolithic sites.
