Castle of Treachery, Felon Castle
A pagan stronghold ruled by Arpian.
It had been built by King Galamanascor (Galamanasar) in Joseph of Arimathea’s time, and it refused to convert to Christianity with the rest of Britain. Saint Augustine gave it its name.
The castle imprisoned maidens and slew any knight of Arthur, whom Arpian hated. The Lady of the Treacherous Castle suffered from a disease and could only be cured by the blood of a virgin princess. Lancelot visited the castle but could not end the custom. When Arpian imprisoned Galahad, Hector, and Meraugis during the Grail Quest, the castle was destroyed by a holy cataclysm.
Arthur kept trying to rebuild it but could not. Much later, Charlemagne successfully reconstructed it and erected a statue of Galahad out front.
See also
Daughter of the King of Lomblanda | The Legend of King Arthur