The Arthurian city of Lyonesse

The Claim

There is a lost city underwater off the coast of England

The city of Lyonesse is mentioned in Arthurian legend, which would immediately make it sound like it’s just a tale, but as with all of the stories on this site, there’s always a little something that suggests it could be true, so why hasn’t anyone found it yet?

Well, the simple answer is it’s thought to have sunk just before the year 1100 AD, though various versions put its sinking anywhere between 1089 and 1099. The island is mentioned in various Celtic and Breton mythology as well as being referenced in various poems and stories, most notably the tale of Tristan and Iseult.

There are also some tales that mention a knight called Tristan as early as the 6th century, but there’s no way of knowing which Tristan is related to which tale.

Tristan was one of Arthur’s knights of the Round Table and was said to be the lord of the land of Lyonesse. He is most well known for saving the princess in the story, and is referenced many times throughout other tales, and also has historical roots, such as the “Tristan stone,” which is a small pillar located in Cornwall and built in the 6th century.

As for the possibility of the island sinking, it is more than a legitimate concept. There is a huge amount of evidence that sea levels were lower hundreds of years ago, and off the coast of Penzance in Mounts Bay, when the tide is at its lowest, it’s still possible to see the tops of petrified tree stumps, which shows evidence of a very different coastline than what we know today.

As for its location, it’s most often believed to be close to the Scilly Isles, even possibly once being a part of them. The Scilly Isles are a small collection of islands about 25 miles southeast of the furthest south-western point of Cornwall. They are made up of 5 major islands still inhabited today, and many smaller ones with little or nothing on them at all.

There is evidence that the islands were at one point one larger island, until what was most likely some geological activity caused the sea level to change and flood the lower areas. Today, between the northern islands, the sea is very shallow, and you can walk from the island of Bryher to Tresco at low tide with no problem. This channel would have been permanently above sea level at one point and most likely covered in grass or woodland, giving weight to the possibility that a similar level of land nearby could once have been inhabited until the shifting of the sea level.

The picture below shows the satellite view from Google Maps of the area between the Scilly Isles and the tip of Cornwall, you can clearly see a raised shape in the sea floor that would have made a sizeable island should the top be out of water.

There have also been tales of fishermen who have claimed to have found pieces of old stone work in their trawler nets, but even if this is true, there’s no telling what, if anything, they are, and none of these “stone works” have ever been substantiated.

What about Treasure?

Well, the island is said to have disappeared overnight with the entire population drowning, and as there was no such thing as scuba gear at the time, it was impossible for anyone who knew where it was to retrieve anything, and since no one has found it since, it would certainly bear incredible riches.

Even if it was something as small as a single town, it would contain the untouched wealth of everyone who lived there, and though most items would be considered artifacts and not actual treasure, there would still be a good amount of jewellery, and the historical importance would be enormous.

As of yet, not a single person has found any actual evidence of its existence, but the disadvantage this place has is that it’s mentioned in Arthurian legend, which immediately places it purely in the realm of fiction for most people. Those capable of mounting an expedition to search for it aren’t willing to spend the money on the promise of a story.