Which 12th-century French romance first presents Perceval as the hero of a Grail story?

Perceval, the Story of the Grail first presents Perceval as the hero of a Grail story in a major 12th-century French romance.

Chrétien de Troyes composed the unfinished Old French poem near the end of the 12th century. Its protagonist, Perceval, begins as an inexperienced young man raised away from chivalric society. He enters Arthur’s world, becomes a knight, and encounters a mysterious procession at the Fisher King’s castle.

The procession includes a bleeding lance and a grail. Chrétien does not explain the object as the cup from the Last Supper, and his poem ends before the central mysteries are resolved. Later writers expanded the material and connected it more explicitly with Christian relic traditions.

The poem’s unfinished state made it unusually influential. Four continuations were written, and later authors reshaped Perceval into one of the principal Grail questers alongside Galahad and Bors.