The fairy wife of Mazadan, Arthur’s great-grandfather, in Wolfram’s Parzival.
She and her husband were ancestors of both Perceval and Arthur – through their sons Lazaliez and Brickus, respectively. Terdelaschoye came from the mountain of Feimurgan.
In creating this name, Wolfram has reversed the elements of the name Feimurgan de Terdelaschoye, or Morgan le Fay of Terre de la Joie.
Source
Parzival | Wolfram von Eschenbach, 1200–1210