Most know Stonehenge for its circle of towering, seemingly immovable monoliths, but perhaps lesser known is that during the site’s early days, it mainly functioned as a cemetery. Thousands of years after the first interments at Stonehenge, the dead are finally revealing their secrets—and, according to a new study published in Scientific Reports, the biggest revelation is that many of those buried at the site originally came from some 140 miles away in western Wales.

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The researchers, led by Christophe Snoeck, a post-doctoral researcher at Brussels’ Vrije University, found that 10 of the 25 individuals tested could not have lived exclusively in Stonehenge for the last ten years of their lives. Instead, the team suggests, the deceased originated in Wales, a neighboring region believed to have provided the site’s bluestones—smaller, non-native rocks nicknamed for the blue hue evident when they are wet or broken.

The Washington Post’s Ben Guarino writes that Snoeck and his colleagues cannot definitively prove that the Welsh individuals buried at Stonehenge were the ones responsible for the bluestones’ delivery and subsequent construction. However, the remains, which date to about 3000 through 2500 B.C.E, appear to coincide with the estimated time period of the monument’s early construction.

“The earliest dates are tantalizingly close to the date we believe the bluestones arrived, and though we cannot prove they are the bones of the people who brought them, there must at least be a relationship,” co-author John Pouncett tells Kennedy. “The range of dates raises the possibility that for centuries people could have been brought to Stonehenge for burial with the stones.”

The Guardian’s Maev Kennedy reports that the researchers used strontium isotope analysis—a technique that relies on the study of strontium, a heavy alkaline earth metal that leaves its signature in geological formations and soil—to study the remains of between 10 and 25 individuals cremated and then interred at Stonehenge. Although cremation destroys all organic matter, including DNA, the process can also crystallize bones, sealing in their isotypes and enabling inorganic matter to survive the flames.

According to The Los Angeles Times’ Deborah Netburn, scientists can determine a human or animal’s place of origin by building a profile of strontium isotope ratios across a given geographic area and comparing this data with the strontium found in bone fragments.

“Strontium isotope analysis has been used for decades to reveal the mobility of human and fauna, but exclusively on unburned material,” Snoeck tells Netburn.

It’s been nearly 100 years since archaeologists first uncovered cremated remains at the site. During the 1920s, researchers excavating a series of Aubrey holes, named after the 17th-century antiquarian who initially discovered them, identified 58 Neolithic-era individuals buried in 56 of the pits. Believing the cremated remains to be of little value, they reburied the jumble of bone fragments in one Aubrey hole.

Guarino reports that the remains were re-excavated in 2008. Christie Willis, a Ph.D. student at University College London’s Institute of Archaeology, began separating the fragments and ultimately identified the 25 sets of remains used in the new study.

It’s unclear whether the Welsh cremated their dead near the Stonehenge site or closer to home, but CNN’s Ashley Strickland writes that the latter is more probable. Colonel William Hawley, the archaeologist behind the 1920s excavations, stated that some of the remains were found in leather bags, suggesting they “had apparently been brought from a distant place”—likely by those bringing bluestones to the site or otherwise aiding construction—for interment.

Moving forward, Snoeck plans on studying cremated remains found across the globe. “They've been kind of forgotten and put aside,” he tells Guarino. “And I thought that was quite sad, because [in] huge parts of the world, people were cremated.”