Perceval, the story of the Grail is the unfinished fifth romance of Chrétien de Troyes.
The poem relates the adventures and growing pains of the young knight Perceval but the story breaks off, there follows an adventure of Gawain of similar length that also remains incomplete. Later authors added 54,000 more lines in what are known collectively as the Four Continuations.
Though Chrétien did not complete his romance, it had an enormous impact on the literary world of the Middle Ages. Perceval introduced the grail and all versions of the story, including those that made the grail "Holy", derive directly or indirectly from it. The grail in Perceval has the power to heal the Fisher King so it may have been seen as a mystical or holy object. Wolfram von Eschenbach Parzival is based largely on Chrétien's poem.