After pausing at a beautiful spring to recover his spirits he reaches a very narrow bridge over a river, but he is too scared to cross this, and so returns shamefaced to Arthur's court.
He then has to kill two lions, a knight, and two dragons, and is finally received by a lady, the original damsel's sister, who offers him herself and one of her thirty-nine castles.
[14][note 1] The literary historian D. D. R. Owen tentatively suggested that the author of both La Mule sans frein and Le Chevalier à l'épée might have been Chrétien de Troyes himself.
[17][18][19][4] The early-13th century romance Diu Crône by the Austrian poet Heinrich von dem Türlin includes in one of its episodes an independent, and rather fuller, version of the entire story of La Mule sans frain.
Sir Kay's failure to achieve his quest has its counterpart in Chrétien's Yvain, Lancelot, Erec and Enide and Perceval, and also in the anonymous La Vengeance Raguidel.
The revolving fortress can be found in the ancient Irish stories The Voyage of Máel Dúin and Bricriu's Feast, and later reappears in various romances of the Holy Grail.
[23][24] The beheading game, played in La Mule by Gawain and the churl, also appears in Bricriu's Feast, and later in the First Continuation to Chrétien's Perceval and in Perlesvaus.
D. D. R. Owen argued that its author, the Gawain Poet, drew directly and in detail on La Mule and Le Chevalier à l'épée for this element of his story, though one scholar has commented on this theory that "one piece of rather flimsy evidence is used to support another, with the result that the whole edifice is kept upright by a combination of hope and ingenuity".