For 350 years, Rome ruled Britain—in fact, they even gave it its name: Britannia. Amazing Roman baths are the reason that there’s a whole town named Bath in Somerset, and the 1,900-year-old Hadrian’s Wall (running 73 miles from the Irish Sea to the North Sea) still bears the name of one the empire’s greatest leaders. There’s a lot of obvious Roman history in Britain, but the Romans also left behind some things that are still a mystery two millennia later.

One of the most perplexing of these puzzles are various dodecahedra spread throughout Britain and continental Europe. Experts estimate that some 130 of these 12-sided objects have been uncovered—33 of them in Britain alone. In the summer of 2023, an amateur archeologist expedition in the town of Norton Disney discovered a 1,700-year-old dodecahedron. After further analysis, the team discerned that the object was a copper alloy made of 75 percent copper, 7 percent tin, and 18 percent lead.

“There are no known descriptions of dodecahedra in Roman literature and therefore their purpose remains extremely unclear,” the archeology team wrote in a blog post following their discovery. “They are not of a standard size, so will not be measuring devices. They don’t show signs of wear, so they are not a tool.”

The first Roman dodecahedron was discovered in 1739, and they always date from between the first and fifth centuries CE. They range in size from a golf ball to roughly the size of a baseball, and the theories for what these objects could be are almost as varied as the objects themselves. As the archeologists noted last year, the Romans never made mention of these 12-sided objects in literature or in art, so no direct knowledge of their purpose is known. According to Mental Floss, that’s led some to believe that they could be anything from “military banner ornaments to candleholders to props used in magic spells.”

Because there are known contemporary allusions to these devices, some scholars have extrapolated their use from archeological context. For example, a Roman dodecahedron was found near a “mounted rider god” figurine in 1989 (according to CNN), and dodecahedra have often been found at temple sites. Their high-quality casting with little-to-no wear and tear suggests that these objects could have some sort of religious significance.

Almost a year after its discovery, the Norton Disney Dodecahedron will be going on display at the Lincoln Museum starting this Saturday (May 4th), and will remain until September of 2024. It’s appearance in the museum coincides with the Lincoln’s first ever Festival of History, which will explore the history of Lindum Colonia—the Roman settlement that eventually became the city of Lincoln.

“The dodecahedron is an extremely tactile object and, having been privileged to have handled it after it’s 1,700 year burial, the imagination races when thinking about what the Romans may have used it for,” Richard Parker, the secretary of the North Disney History and Archaeology Group that found the dodecahedron, said in a press statement about the object’s display at the museum. “Magic, rituals or religion; we perhaps may never know.”