Then rose the King and moved his host by night,
And ever push'd Sir Mordred, league by league,
Back to the sunset bound of Lyonesse--
A land of old upheaven from the abyss
By fire, to sink into the abyss again;
Where fragments of forgotten peoples dwelt,
And the long mountains ended in a coast
Of ever-shifting sand, and far away
The phantom circle of a moaning sea.
                               Tennyson, Idylls of the King

      Lyonesse is the name of a legendary land, most famous for sinking under the sea. In Arthurian romance, it was the western-most kingdom of Arthur's realm, extending beyond the end of Cornwall and joining the Isles of Scilly to the rest of Britain.

Lyonesse in Legend

      In many versions of Tristan and Iseult, Tristan is the son of the King of Lyonesse. In other stories, Lyonesse is the land where Mordred pursues Arthur's armies in the last battle (as in Tennyson's version; see above). The sinking of Lyonesse plays a part in some legends; after the fall of King Arthur, Merlin's ghost is to have appeared and have sunk the land beneath the feet of Mordred's forces, while allowing Arthur's army to escape to the Isles of Scilly.

Location of Lyonesse

      Given the distinct possiblity that the land at the end of Cornwall was never called Lyonesse, how else might it have found a place in the Arthurian legend? It was Tristan's homeland-- also called Liones in other legends. Lyonesse/Liones could originally have been Lothian in Scotland (Leonais in Old French) or Leonais in Brittany.

The Real Lyonesse?

      According to The Arthurian Encyclopedia (Garland Publishing, New York, 1986), "Lyonesse is not completely devoid of factual foundation." Cornish folklore has the legend of Lethowstow, a land that was supposed to have not only joined Cornwall from Land's End to the Isles of Scilly, but to have also joined the Isles of Scilly to themselves. The ocean is supposed to have submerged this low-lying land of numerous towns at an unknown date. There is also one slim reference in Roman times to Scilly having been one single island-- Sylina Insula, the Isle of Scilly, possibly giving life to the legend, if later this island was broken up into several. Reference is made to Lyonesse in Britannia by Camden in 1586 and in Survey of Cornwall by Carew in 1602.