Roughly 2000 years ago, a building sign in the Roman town of Calleva Atrebatum was shattered into pieces—quite possibly by Boudica, the Celtic queen who once headed a bloody uprising against the Roman Empire, and her legions of soldiers.

In 1891, archaeologists found a piece of the marble sign while excavating the abandoned civilization, which is now known as Silchester Roman Town thanks to its location in the parish of Silchester in Hampshire, U.K. The fragment was etched with the letters “At”—but scholars couldn’t make out the entire original word without other pieces. The find eventually landed in the Reading Museum's Silchester Collection, where it stymied historians for a century. 

In 2013, Reading archaeologists finally found their answer when they unearthed another fragment in the town’s ruins, about 30 feet away from the original segment. This marble slab was engraved with the letters “ba.” After careful analysis, they determined that the two pieces matched—a rare find, considering the shards had been separated for millennia.

“Matching pieces which were discovered over 100 years apart to a 2000-year-old object is incredibly rare—perhaps happening only once or twice in the UK before,” Mike Fulford, a professor from the University of Reading’s archaeology department, said in a release. “The 2013 piece is special in its own right—evidence of very early destruction of a monumental building in the mid or mid-to-late first century A.D. in Britain is exceptional—but little did we know about what was about to come to light."

The sign once read “At(e)ba(tum)—'of the Atrebates’—the name of the French tribe that most likely settled Silchester in the first century BCE. It likely marked a significant structure, or a dedication to a god. However, the words at the sign’s top still remain a mystery—one that could reveal the building’s name, and possibly more about the town’s history and importance, if more pieces are ever found. 

[h/t Archaeology]