is sent to Ireland to escort the Irish king's daughter, the beautiful Isolt, to Cornwall to become his uncle's bride
Tristan, the heroic nephew of King Mark of Cornwall,
The most influential medieval telling of Tristan and Isolde's tragedy was that written by the mysterious "knyght presoner" Sir Thomas Malory as part of his collection of tales delineating the rise and fall of King Arthur, commonly known as the Morte d'Arthur.
The real Tristan may have been the Pictish prince, named Drust, the son of Talorc. Drust was believed to have lived in Scotland, in c. 780. Here, the story of Morholt, originated, with Drust saving a princess from pirates.
And as by sadness you came into the world, your name shall be called Tristan; that is the child of sadness
After she had said these words she kissed him, and immediately when she had kissed him she died
this could probably be part of his "mysterious origin"
Then he cut out the tongue and put it into his hose, but as the poison came against his flesh the hero fainted and fell in the high grass that bordered the marsh around.
There Iseult told her mother the tale and left the hero with her, and as the Queen unharnessed him, the dragon’s tongue fell from his boot of steel.