The term Chapel Perilous first appeared in Sir Thomas Malory's Le Morte d'Arthur (1485) as the setting for an adventure in which sorceress Hellawes unsuccessfully attempts to seduce Sir Lancelot. T. S. Eliot used it symbolically in "The Waste Land" (1922). Dorothy Hewett took The Chapel Perilous as the title for her autobiographical play, in which she uses "the framework of the Arthurian legend, Sir Lancelot, to create a theatrical quest of romantic and epic proportions".
The term as used in literature is explicated in detail by Jessie L. Weston in her book From Ritual to Romance (1920). It is also defined by Thomas C. Foster (in a discussion of the five elements of a quest) as "the dangerous enclosure that is known in the study of traditional quest romances." He cites the plot of the book Crying of Lot 49 (1966) as an example.
"Chapel Perilous" is also an occult term referring to a psychological state in which an individual cannot be certain whether they have been aided or hindered by some force outside the realm of the natural world, or whether what appeared to be supernatural interference was a product of their own imagination. It was used as an occult term by the late writer and philosopher Robert Anton Wilson (1932–2007) in his book Cosmic Trigger (1977). According to Wilson, being in this state leads the subject to become either stone paranoid or an agnostic. In his opinion there is no third way.
The term "Chapel Perilous" was used by Antero Alli, in his 1986 book, Angel Tech: A Modern Shaman's Guide to Reality Selection which is based on Timothy Leary's Eight-circuit model of consciousness. In Alli's book Chapel Perilous is regarded as a rite of passage, when moving between the four lower circuits of consciousness to the higher circuits. In Chapel Perilous the integrity of the lower circuits is tested in preparation for activation of the higher circuits.
- Malory, Sir Thomas. Le Morte D'arthur: Sir Thomas Malory's Book of King Arthur and of his Noble Knights of the Round Table, Volume 1.
- "NSW HSC Online". NSW Government, Education and Communities, and Charles Sturt University.
- Jessie L. Weston (1920). "Chapter thirteen: The Perilous Chapel". From Ritual to Romance. Internet Sacred Text Archive.
- Foster, Thomas C. (2003). How to Read Literature Like a Professor: A Lively and Entertaining Guide to Reading Between the Lines. Harper-Collins. p. 4. ISBN 0-06-000942-X.