What is "lanval"

Lanval is one of the Lais of Marie de France. Written in Anglo-Norman, it tells the story of Lanval, a knight at King Arthur's court, who is overlooked by the king, wooed by a fairy lady, given all manner of gifts by her, and subsequently refuses the advances of Queen Guinevere. The plot is complicated by Lanval's promise not to reveal the identity of his mistress, which he breaks when Guinevere accuses him of having "no desire for women". Before Arthur, Guinevere accuses Lanval of shaming her, and Arthur, in an extended judicial scene, demands that he reveal his mistress. Despite the broken promise, the fairy lover eventually appears to justify Lanval, and to take him with her to Avalon. The tale was popular, and was adapted into English as Sir Landevale, Sir Launfal, and Sir Lambewell.