What a fascinating discovery at 'King Arthur's Castle' can teach us about human culture.

Archeologists in the U.K. just unearthed ... a really old wall at Tintagel Castle.

Photo by Matt Cardy/Getty Images.

And it's a big deal.

Researchers believe the wall in question is a part of the "seat of the rulers of the early medieval kingdom of Dumnonia," who ruled parts of southwestern England over 1,400 years ago, according to a BBC report.

An archeologist works at the excavation site. Photo by Emily Whitfield-Wicks/English Heritage.

"This is the most significant archaeological project at Tintagel since the 1990s," Win Scutt, a director on the project, explained in a release. "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."

Legend has it that Tintagel was the birthplace of King Arthur. And while Arthur is, at best, questionably real, the old royal seat is very real.

A sculpture of Merlin at Tintagel Castle. Photo by Matt Cardy/Getty Images.

And, this, per the BBC, is pretty cool:

"Discoveries at the site also include large amounts of pottery from the eastern Mediterranean used for olive oil and wine, as well as Merovingian glass and fine Phocaean tableware from the west coast of Turkey."

It's yet another piece of evidence that national cultures — even very old ones — are hodgepodge stews of influences from all around the world.

Items excavated at the dig site. Photo by Emily Whitfield-Wicks/English Heritage.

It's tempting to think that British people have been "British" as we conceive it today — eating fish and chips, sipping Earl Grey tea, and singing "God Save the Queen" every night before bed — since the dawn of time.

In reality, it appears that at least some ancient Britons were merrily, Greek-ily lapping up olive oil while drinking from French wine glasses and eating off of plates from the Middle East.

It isn't particularly surprising — after all, Britain was a Roman colony until the fifth century A.D., and the Romans had footprints all over Europe, the Middle East, and North Africa.

But it's still important to remind ourselves of this — specifically, whenever a politician promises to beat back foreign trade, keep out a certain group of people, or make this, that, or the other country great again.

It's certainly possible, technically speaking, that a culture, city, or country may have been "great" or "greater" in the past.

A sculpture outside Tintagel Castle. Photo by Matt Cardy/Getty Images.

But if it was, it probably wasn't because it was somehow perfectly isolated, free of contribution from elsewhere in the world.

Even if that contribution is flatware and a condiment to dip crusty bread in.

In that way, the Tintagel discovery isn't just a triumph for our understanding of obscure sixth-century British history.

Photo by Matt Cardy/Getty Images.

It's a reminder that the notion of a "pure" national culture, one uncorrupted by outside influence, is as mythical as Merlin and Arthur.