A leper from the city of Lantyan in Cornwall.
He attended what was to be Isolde’s burning at the stake for her affair with Tristan. He convinced Mark that a better punishment for Isolde would be to turn her over to him and the other lepers. Mark agreed and gave Isolde to the lepers. Tristan showed up and beat them away before they could take advantage of her.
Source
Tristan | Béroul, late 12th century