 In the prose stories of Tristan and Iseult, they live in the castle with Lancelot's permission as refugees from King Mark.The late-medieval writer, Thomas Malory, identified the Joyous Gard with Bamburgh Castle, a coastal castle in Northumberland that was built on former location of a Celtic Briton fort known as Din Guarie.Joyous Gard is also associated with Château de Joyeuse Garde, an early medieval castle site in Brittany.