You don’t have to be a Harry Potter fan to be familiar with Platform 9 3/4. Just in case you’ve managed to miss it, though, here’s an overview: To catch the train to get to Hogwarts, wizards go to the King’s Cross tube station in London, then run at a wall between platforms 9 and 10. They magically pass right through and find themselves standing in front of their enchanted transportation. If Harry had decided to do a little digging while he was waiting for the Hogwarts Express to show up, he might just have found more than mandrakes.

In 60 CE, Boudica (also spelled Boudicca and Boadicea), queen of the Iceni tribe in eastern England, was publicly flogged by the invading Romans after her husband King Prasutagus died. Her two daughters were also raped. In 61 or 62 CE, bent on revenge, the Celtic queen united multiple tribes against the Romans, and burned some of their Roman settlements to the ground. One author compares the utter devastation to the volcanic eruptions that buried Pompeii; it's estimated that at least 70,000 Romans were killed.

Boudica's success came to an end when her vast army was decimated by a much smaller Roman contingent. Legend has it that the defeated queen fled from the battlefield proper, then drank from a poisoned cup, making her gravesite not far from the scene of the massacre. But, as with most things that happened thousands of years ago, we’re not exactly sure where any of that happened. All we have to go on are a couple of rather vague ancient accounts, including one in a Roman Empire history tome called Annals, written by the Roman senator and historian Tacitus.

Carole Raddato, Wikimedia Commons // CC BY-SA 2.0

In 1937, author and journalist Lewis Spence published a book with the hypothesis that the pivotal battle may have taken place where King’s Cross now stands. He even included a detailed map of the area, showing where each army may have been positioned for the final showdown. The theory somehow turned into urban legend over the years, likely aided by the fact that before the area was deemed “King’s Cross,” it was called “Battle Bridge,” which many assume referred to Boudica’s last stand.

Most experts dismiss the King’s Cross theory, and even the idea that the battle took place anywhere near the London area. Birmingham has been floated as a more likely spot for the queen’s last stand—Tacitus described the scene as a hilly area surrounded by trees, with a single opening, and a site in Birmingham called Parson’s Hill matches this description perfectly. Unless artifacts are discovered at a dig site, however, we may never know where Boudica’s battle took place. Archaeologists cross-referenced Tacitus’s descriptions with digital terrain models and came up with 263 possible locations.

Though the King's Cross story persisted for decades, J.K. Rowling's placement of the Hogwarts Express platform is likely coincidence—the author has never acknowledged that she was even aware of the Boudica legend when she wrote Harry Potter. She did have a specific reason for choosing the King’s Cross railway station, though: “My parents met on a train to Scotland which departed from King's Cross station,” she explains on Pottermore. “For this reason, and because it has such an evocative and symbolic name, and because it is actually the right station to leave from if you were heading to Caledonia, I never knew the slightest indecision about the location of the portal that would take Harry to Hogwarts, or the means of transport that would take him there.”