The Siège Perilous, or the Perilous Seat, is a vacant seat at the Round Table reserved for the true Grail Knight. It is fatal for anyone else who sits in it. The chair is fixed from stone by Merlin. In the Queste del Saint Graal it is Galahad for whom the seat is reserved, and in the Didot-Perceval it is Percival who sits there, causing darkness and the splitting of a stone, whereupon a voice rebukes Arthur for permitting this act.
- Lacy, Norris J., ed. (1996). The New Arthurian Encyclopedia. New York: Garland.