With walls about three feet thick, a royal palace being unearthed in England is raising eyebrows: Could the palace have some association with the legendary King Arthur?

The exploration, run by the Cornwall Archaeological Unit, is taking place at the Tintagel site in Cornwall, England, where they’ve dug trenches to better understand the location’s rich history. In addition to those thick walls, researchers have also found 150 fragments of glass and pottery that came from distant places, the Telegraph reported— a hint that well-to-do people lived there.

The structures they are exploring are thought to date from the fifth or sixth century, and were perhaps part of a kingdom called Dumnonia. The Tintagel site is also the home of famous 13th-century castle ruins. 

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“The discovery of high-status buildings – potentially a royal palace complex – at Tintagel is transforming our understanding of the site,” Win Scutt, the English Heritage’s Properties Curator for the West, said according to the Telegraph.

The project has spurred the Telegraph as well as The Sun to point out that the palace’s location is the same as the fabled birthplace of King Arthur. The Sun speculated that the palace could have been abandoned because of the bubonic plague that ravaged medieval England.

“This is the most significant archaeological project at Tintagel since the 1990s,” Scutt said in a July statement. “The three week dig this summer is the first step in a five year research programme to answer some key questions about Tintagel and Cornwall’s past.

“We’ll be testing the dig sites to plan more advanced excavations next year, getting a much clearer picture of the footprint of early medieval buildings on the island, and gathering samples for analysis. It’s when these samples are studied in the laboratory that the fun really starts, and we’ll begin to unearth Tintagel’s secrets.”

The legendary King Arthur’s birthplace is unknown, and last year, experts debunked a myth about his supposed grave: he was not buried at Glastonbury Abbey. The story that his gravesite was located there was invented by monks following a 1164 fire, the Guardian reported in 2015.