Lady of the Chapel
An ancestor of Perceval.
Her daughter’s lover murdered Guinevere’s husband and framed Guinevere for the murder. Guinevere’s four sons walled her up in a chapel. God made the tomb holy, and all who visited it were healed of wounds or disease. Galahad, Perceval, and Bors visited the chapel at the conclusion of the Grail Quest.
Source
Post-Vulgate Queste del Saint Graal | 1230-1240