Lyonesse  Lyonesse is a country in Arthurian legend, particularly in the story of Tristan and Iseult. Said to border Cornwall, it is most notable as the home of the hero Tristan, whose father was king. In later traditions, Lyonesse is said to have sunk beneath the waves some time after the Tristan stories take place, making it similar to Ys and other lost lands in medieval Celtic tales, and perhaps connecting it with the Isles of Scilly. In medieval Arthurian legend, there are no references to the sinking of Lyonesse, because the name originally referred to a still-existing place. Lyonesse is an English alteration of French Léoneis or Léonois (earlier Loönois), a development of "Lodonesia", the Latin name for Lothian in Scotland. Continental writers of Arthurian romances were often puzzled by the internal geography of Great Britain; thus it is that the author of the French Prose "Tristan" appears to place Léonois contiguous, by land, to Cornwall. In English adaptations of the French tales, Léonois, now "Lyonesse", becomes a kingdom wholly distinct from Lothian, and closely associated with the Cornish region, though its exact geographical location remained unspecified. The name was not attached to Cornish legends of lost coastal lands until the reign of Elizabeth I of England. However, the legendary lost land between Land's End and Scilly has a distinct Cornish name: "Lethowsow". This derives from the Cornish name for the Seven Stones Reef, on the reputed site of the lost land's capital and the site of the notorious wreck of the . The name means 'the milky ones', from the constant white water surrounding the reef. Alfred, Lord Tennyson's Arthurian epic "Idylls of the King" describes Lyonesse as the site of the final battle between Arthur and Mordred. One passage in particular references legends of Lyonesse as a land fated to sink beneath the ocean:  Then rose the King and moved his host by night And ever pushed 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.