In Arthurian legend, Lyonesse is the home country of Tristan, from the legendary story of Tristan and Iseult. The mythical land of Lyonesse is now referred to as the “Lost Land of Lyonesse,” as it is ultimately said to have sunk into the sea. However, the legendary tale of Tristan and Iseult shows that Lyonesse is known for more than sinking into the ocean, and that it had a legendary presence while it remained above ground. While Lyonesse is mostly referred to in stories of legend and myth, there is some belief that it represents a very real city that sunk into the sea many years ago. With such a legendary location, it can be difficult to ascertain where the legend ends and reality begins.

The story of Lyonesse most logically begins with Tristan and Iseult. The story of Tristan and Iseult is a tragic story of love and loss. It is an Arthurian tale, inspired by Celtic legend. It is said that the story was possibly the inspiration for the romance of Lancelot and Guinevere, as both stories push the boundaries of love, family, loyalty, adultery, and betrayal. While the story of Tristan and Iseult can vary based upon who is telling it, the plot follows a common theme. Tristan, a young boy from Lyonesse who has been orphaned, it taken in by his uncle, King Tonylazer of Cornwall, which borders Lyonesse.