Devlites, Dialantes, Dialicies
His sons all converted to Christianity, so Dialetes killed them and every other Christian he could find. He built the Castle of Tears on the Giant’s Isle as a stronghold against Christianity, which retained its evil customs until destroyed by Tristan.
This account first appears in the Prose Tristan; La Tavola Ritonda expands on it and asserts that Dialetes slew Joseph of Arimathea himself.
Prose Tristan | 1230-1240
La Tavola Ritonda | 1325–1350