The group of local volunteers from the small village of Norton Disney in Lincolnshire unearthed a Roman dodecahedron – a 12-sided metal shell – which has left modern archaeologists are at a loss to explain what they might have been used for.
Richard Parker, the secretary of the Norton Disney History and Archaeology Group, said they dug up the object, which is the size of a grapefruit, about 35 miles southeast of Sheffield in one of the trenches the group made at the site for the two-week dig.
“It was our second-to-last day of the excavation, and up pops this dodecahedron in Trench Four,” Mr Parker told Live Science. “We were completely surprised by it. We weren’t getting many metal [signals] at that point, but all of a sudden there it was.”
There are about 32 known examples of dodecahedrons, either whole or in parts in Roman Britain. The Norton Disney find now makes 33.
The dodecahedron is the only example found in the Midlands and is in excellent condition with no damage and still completely intact.
These objects date from between the first and the third centuries AD but their purpose remains a mystery as no mention of dodecahedrons has been found in contemporary accounts or pictures of the time.
Some speculate they may have been used as a measuring device, but the lack of markings to indicate this brings the theory into question.
Other suggested uses include being used as children’s toys, a knitting device or for decorative purposes.
Alternatively, some archaeologists think they had religious purposes in some areas as they had previously been found in graves and the lack of records of them may be explained by Roman law prohibiting most magic.
Mr Parker said the group found the object in a field where metal detectorists had already found Roman coins and broaches. A previous geophysical survey had also revealed what looked like a buried pit at the site.
They believe the object was found where it was deliberately placed some 1700 years before with Roman pottery in a quarry pit.
He told The Independent that the group plan to return to the site this summer to complete the excavations they began in 2023.
He said they will be returning to the site this summer to try and find out more about the circumstances of why it was left there and if there to hopefully any clues about its purpose and use.
The group said: “Roman society was full of superstition, something experienced on a daily basis. A potential link with local religious practice is our current working theory. More investigation is required though.”
You can find out more about the group and visit their excavation fundraiser here.