Perceval, or the Story of the Grail

Chrétien's grail is 'un graal', a dish; Robert de Boron, writing between 1191 and 1202, first made it the Last Supper vessel that caught Christ's blood.

Chrétien de Troyes, Perceval, ed. Charles Potvin (1866), vol. 2, the grail procession; Wikipedia, 'Holy Grail', section 'Robert de Boron and continuators'

Chrétien de Troyes's unfinished verse romance of about 1180 to 1191, the first text with a grail.

Sources3 sources

Primary source

Chrétien de Troyes, Perceval, the Story of the Grail (English translation; Cambridge: D. S. Brewer), 1986Chrétien's unfinished romance, written for Philip of Flanders between about 1180 and 1191, in which the grail first appears, at the castle of the Fisher King.
Chrétien de Troyes, ed. Charles Potvin, Perceval le Gallois ou le Conte du Graal, vol. 2 (Mons: Dequesne-Masquillier), 1866, lines 4398 (procession) and 7766-7802 (the hermit)The grail is carried in as 'un graal'; the hermit explains that it serves the Fisher King's father a single host that sustains his life, so holy a thing it is, and that Perceval's sin over his mother kept him from asking.
D'une sole oiste li sains hom

Scholarship

Wikipedia contributors, Holy Grail, section 'Robert de Boron and continuators'Robert de Boron's Joseph d'Arimathie, composed between 1191 and 1202, first makes the grail the chalice of the Last Supper used to collect Christ's blood; Chrétien's poem is dated between 1180 and 1191.
composed between 1191 and 1202