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Sources and influence

The immediate and specific sources for his romances are uncertain, as Chrétien speaks in the vaguest way of the materials he used. Geoffrey of Monmouth or Wace might have supplied some of the names, but neither author mentioned Erec, Lancelot, Gornemant and many others who play an important role in Chrétien's narratives. One is left to guess about Latin or French literary originals which are now lost, or upon continental lore that goes back to a Celtic source in the case of Béroul, an Anglo-Norman who wrote around 1150. For his Perceval, the Story of the Grail, the influence of the story is clearly tied to the story of Saint Galgano (Galgano Guidotti) who died in 1180–1181 and was canonized in 1185: a knight struck by god's vision, planted his sword in the ground that immediately solidified (kept in Abbey San Galgano). However, Chrétien found his sources immediately at hand, without much understanding of its primitive spirit, but appreciating it as a setting for the ideal society dreamed of, although not realized, in his own day. And Chrétien's five romances together form the most complete expression from a single author of the ideals of French chivalry. Though so far there has been little critical attention paid to the subject, it is not inaccurate to say that Chrétien was influenced by the changing face of secular and canonical law in the 12th century. This is particularly relevant for his Lancelot, the Knight of the Cart, which makes repeated use of the customary law prevalent in Chrétien's day.

William Wistar Comfort praised de Troyes' "significance as a literary artist and as the founder of a precious literary tradition distinguishes him from all other poets of the Latin races between the close of the Empire and the arrival of Dante." Chrétien's writing was very popular, as evidenced by the high number of surviving copies of his romances and their many adaptations into other languages. Three of Middle High German literature's finest examples, Wolfram von Eschenbach 's Parzival and Hartmann von Aue 's Erec and Iwein, were based on Perceval, Erec, and Yvain; the Three Welsh Romances associated with the Mabinogion (Peredur, son of Efrawg, Geraint and Enid, and Owain, or the Lady of the Fountain) are derived from the same trio. Especially in the case of Peredur, however, the connection between the Welsh romances and their source is probably not direct and has never been satisfactorily delineated. Chrétien also has the distinction of being the first writer to mention the Holy Grail (Perceval), Camelot (Lancelot), and the love affair between Queen Guinevere and Lancelot (Lancelot), subjects of household recognition even today.

There is a specific Classical influence in Chrétien's romances, the likes of which (the Iliad, the Aeneid, the Metamorphoses) were "translated into the Old French vernacular during the 1150s". Foster Guyer argues that specifically Yvain, the Knight of the Lion contains definite Ovidian influence: "Yvain was filled with grief and showed the Ovidian love symptoms of weeping and sighing so bitterly that he could scarcely speak. He declared that he would never stay away a full year. Using words like those of Leander in the seventeenth of Ovid's Epistles he said: 'If only I had the wings of a dove/to fly back to you at will/Many and many a time I would come'."

Chrétien has been termed "the inventor of the modern novel ". Karl Uitti argues: "With a new era opens in the history of European story telling… this poem reinvents the genre we call narrative romance; in some important respects it also initiates the vernacular novel." A "story" could be anything from a single battle scene, to a prologue, to a minimally cohesive tale with little to no chronological layout. Uitti argues that Yvain is Chrétien's "most carefully contrived romance… It has a beginning, a middle, and an end: we are in no doubt that Yvain's story is over." This very method of having three definite parts, including the build in the middle leading to the climax of the story, is in large part why Chrétien is seen to be a writer of novels five centuries before novels, as we know them, existed.