Chretien de Troyes's Le Chevalier au Lion (Yvain and the Lion, ca. 1177) was most likely written when Chretien was a poet in the court of the Count of Flanders, and like other tales of Chretien's—Le Chavalier de la Charrette (The Knight of the Carriage—Launcelot)—was part of twelfth-century continental Arthurian literature. At this time, court poets focused their material on such concepts as courtesy, courtliness, adherence to the code of knighthood, the supremacy of King Arthur and his court, the pursuit of courtly love, defeat of supernatural beings, and, perhaps most important, individual knights' quests for perfection.

In Yvain, we have a knight who goes on a quest to avenge another knight, Calogrenant, by killing a royal woman's (Laudine) husband, and then falling in love and marrying her. Persuaded by Gawain to return to Arthur's court to continue building his reputation as a knight, Yvain—given permission by Laudine to be gone for a year—goes on a knightly quest "binge" and fails to return to Laudine in the year's time, and she repudiates her marriage to Yvain in disgust. Yvain, the not-so-ideal knight, essentially goes crazy with remorse, lives in a forest as a wild beast, is found by a noble lady (the Lady Noroison) and her ladies, and begins a process of rehabilitation to his knightly status. During this process, he hears

a cry of desperation and suffering [from a lion whom a serpent holds by the tail] because [the lion's] legs are burning with a scorching fire [because of the serpent's venom]. (ll. 3350-51)

Yvain quickly decides to save the noble beast—it's not a coincidence that the lion, in medieval heraldry, is a symbol of nobility—and kills the serpent in combat. In a symbolic gesture, Yvain, who has been in an evil mood, carefully wipes the venom (evil) off his sword, thereby rejoining the world of knights. The lion and Yvain then become inseparable in a long series of adventures in which the lion helps him. At one point, when the lion thinks Yvain has been killed, the lion tries to kill himself with Yvain's sword, only to be saved when Yvain regains consciousness and takes the sword away. After adventures in which Yvain and the lion confront and defeat a giant, two half demons, and even Gawain, Yvain is reunited with Lady Laudine.

As several scholars have pointed out, the lion represents not just strength and loyalty but also Yvain's true nobility and knightly virtues—they have fought beside each other in dire situations and risked their lives for each other routinely during these encounters. Loyalty, above all else, is the true knightly virtue, and Yvain has now shown that he has regained that primary quality with the help of his companion.

Lastly, knights in Arthurian literature tend not to be perfect—Gawain in Sir Gawain and the Green Knight, for example—and Yvain is, at the beginning of the poem, very imperfect as a knight. But Chretien de Troyes weaves a story that can only be seen as a tale of redemption for Yvain. He moves from knight to animal to knight again through the influence of friendship, loyalty, and adherence to a code of behavior that, even once abandoned, can be regained.