A mathematical analysis of a collection of mysterious decorated stone cylinders known as the Folkton Drums suggests the ancient objects could have been used as a standardized unit of measurement in building ancient stone monuments.

Writing in the British Journal for the History of Mathematics, researchers from the University College London and Manchester University say the stone cylinders would have enabled ancient builders to accurately measure stone circles and other ancient structures of ritualistic or cultural significance such as Stonehenge.

“We propose that there is a direct link between the design of the monument of Stonehenge and the chalk artifacts known as the Folkton and Lavant Drums, in which the Drums represent measurement standards that were essential for accurate and reproducible monument construction,” write the authors.

First found in 1889 in a child’s grave in northern England, the “beautiful yet fathomable” drums are made of locally quarried chalk and decorated with geometric designs. Though no radiocarbon dating is available yet, the drums are believed to date back to the third millennium BC. Measuring rope, which can vary in length depending on humidity and other weather conditions, may have been wrapped around the outside of a drum in order to maintain a consistent length. Meanwhile, decorations found on the outside may “encode instructions concerning rotations.” The largest of the drums have circumferences close to 3 meters (10 feet), but the size variations allow for different building techniques to “form a mathematical harmonic sequence.”

“We consider this sizing to have been deliberately incorporated into their design in order to allow the use of the drums as standards of linear measurement,” the authors wrote.

Given their proximity to Stonehenge, it’s possible these stones (or ones similar to them) could have been used to measure and build the prehistoric monument located in Wiltshire, England. Understanding the drums, researchers say, could provide clues about how similar massive structures were made. Little is known about how or why Stonehenge was built, for example, other than it was constructed by an ancient group of people over several stages and centuries likely oriented toward solstice events. 

However, the researchers note that the drums were left in the graves of children, so they could have some implications for children, growth, or the human life-cycle – all theories and mysteries yet to be explored in future research.