The Grail is one of the most compelling and paradoxical objects in Western literature, as well as one of the best known. Uniting chivalric romance and mystical writing inspired by the Gospels, it wounds and heals; it is the object of a quest which is a foregone conclusion and of a question which is not asked. It magically distributes food, but also serves a man who is nourished solely by the Eucharistic host, and is associated with the famine of a wasteland. As it occurs in a succession of twelfth- and thirteenth-century romances in French, the medium of the Grail's description changes from verse to prose. The Grail itself changes shape and significance, and its quester changes his name and genealogy. It is also the centre of a constellation of supernatural objects (a special seat at Round Table, an enchanted castle, broken swords, a lance that bleeds), and is attended by extraordinary people (wounded kings who live for hundreds of years, virginal female guardians, omniscient hermits and chaste knights).

The noun graal derives from the Latin gradalis, a large platter which could hold a selection of different foods. Later texts, in which the Grail has become ‘le Saint Graal’, offer an alternative etymology for graal, based on graer/greer to grant, to fulfil. The image of a dish or cup which has supernatural powers has been traced to Celtic folkloric roots.