La Bele Garde, La Bele Prise
A castle in the kingdom of King Lancelot de la Blance Terre – grandfather of Lancelot – according to the Vulgate Estoire del Saint Graal.
King Lancelot loved the lady of the castle, who was married, and her husband eventually slew Lancelot in jealousy.
In the Vulgate Lancelot, the castle is known as the White Fortress. Sommer says that La Bele Garde was given the name La Dolerouse Tor (Dolorous Tower) after its conquest by Lancelot.
Source
Vulgate Estoire del Saint Graal | 1220-1235