[76]Arthur's role in these works is frequently that of a wise, dignified, even-tempered, somewhat bland, and occasionally feeble monarch. So, he simply turns pale and silent when he learns of Lancelot's affair with Guinevere in the Mort Artu, whilst in Chrétien de Troyes's Yvain, the Knight of the Lion, he is unable to stay awake after a feast and has to retire for a nap.[77] Nonetheless, as Norris J. Lacy has observed, whatever his faults and frailties may be in these Arthurian romances, "his prestige is never-or almost never-compromised by his personal weaknesses . his authority and glory remain intact."[78].
Arthur and his retinue appear in some of the Lais of Marie de France,[80] but it was the work of another French poet, Chrétien de Troyes, that had the greatest influence with regard to the above development of the character of Arthur and his legend.[81] Chrétien wrote five Arthurian romances between c. 1170 and 1190. Erec and Enide and Cligès are tales of courtly love with Arthur's court as their backdrop, demonstrating the shift away from the heroic world of the Welsh and Galfridian Arthur, while Yvain, the Knight of the Lion, features Yvain and Gawain in a supernatural adventure, with Arthur very much on the sidelines and weakened. However, the most significant for the development of the Arthurian legend are Lancelot, the Knight of the Cart, which introduces Lancelot and his adulterous relationship with Arthur's queen (Guinevere), extending and popularising the recurring theme of Arthur as a cuckold, and Perceval, the Story of the Grail, which introduces the Holy Grail and the Fisher King and which again sees Arthur having a much reduced role.[82] Chrétien was thus "instrumental both in the elaboration of the Arthurian legend and in the establishment of the ideal form for the diffusion of that legend",[83] and much of what came after him in terms of the portrayal of Arthur and his world built upon the foundations he had laid.