Sir Launfal is a 1045-line Middle English romance or Breton lay written by Thomas Chestre dating from the late 14th century. It is based primarily on the 538-line Middle English poem Sir Landevale, which in turn was based on Marie de France's lai Lanval, written in a form of French understood in the courts of both England and France in the 12th century. Sir Launfal retains the basic story told by Marie and retold in Sir Landevale, augmented with material from an Old French lai Graelent and a lost romance that possibly featured a giant named Sir Valentyne. This is in line with Thomas Chestre's eclectic way of creating his poetry.Mills, M, 1969. Lybeaus Desconus, from the Medieval manuscripts Lambeth Palace MS 306 and British Museum MS Cotton Caligula A.ii. Published for the Early English Text Society by Oxford University Press. p 35.

In the tale, Sir Launfal is propelled from wealth and status – the steward at King Arthur's court – to being a pauper and a social outcast. He is not even invited to a feast in his home town of Caerleon when the king visits, although Arthur knows nothing of this. Out in the forest alone, he meets with two damsels who take him to their mistress, the daughter of the King of Faerie. She gives him untold wealth and a magic bag in which money can always be found, on the condition that he becomes her lover. She will visit him whenever he wants and nobody will see her or hear her. But he must tell nobody about her, or her love will vanish at that instant.

The story of a powerful (fairy) woman who takes a lover on condition that he obey a particular prohibition is common in medieval poetry: the French lais of Desiré, Graelent, and Guingamor, and Chrétien de Troyes's romance Yvain, the Knight of the Lion, all share similar plot elements. The presence of a Land of Faerie, or an Otherworld, betrays the story's Celtic roots. A final court scene may be intended by Chestre as criticism of the contemporary legal and judicial framework in late-14th-century England. The equation of money with worth in the tale may satirize a late-14th-century mentality.

Manuscripts Sir Launfal survives in a single manuscript copy: British Museum MS Cotton Caligula A.ii., mid-15th century.

The Middle English poem itself dates to the late-14th century,Laskaya, Anne and Salisbury, Eve (Eds). 1995. Introduction to Sir Launfal.Tuma, George W. and Hazell, Dinah (Eds). 2009. "Harken to Me" Middle English Romances in Translation. Medieval Forum Special Edition. Sir Launfal Translation in Modern English with a Commentary. and is based principally upon an early-14th-century English romance Sir Landevale, itself an adaptation of Marie de France's Old French Breton lai, Lanval. Unusually for a Middle English romance, the poem's author can be named. The final stanza includes the lines: "Thomas Chestre made thys tale Of the noble knyght Syr Launfale, Good of chyvalrye."Laskaya, Anne and Salisbury, Eve (Eds). 1995. Middle English text of Sir Launfal, lines 1039–41.

It is widely accepted that Thomas Chestre was the author of two other verse romances in MS Cotton Caligula A.ii., Lybeaus Desconus and the Southern Octavian.Lupack, Alan, 2005, reprinted in paperback, 2007. Oxford Guide to Arthurian Literature and Legend. Oxford University Press. "An English version of the Fair Unknown theme appears in the stanzaic romance Lybeaus Desconus, believed to have been written by Thomas Chestre, author of Sir Launfal, in the latter half of the fourteenth century." p 320.Mills, M, 1969. Lybeaus Desconus, from the Medieval manuscripts Lambeth Palace MS 306 and British Museum MS Cotton Caligula A.ii. Published for the Early English Text Society by Oxford University Press. p 34.

Plot Sir Launfal participates in the chivalric tradition of gift-giving to such an extent that he is made King Arthur's steward, in charge of celebrations. After ten happy years under Launfal's stewardship, however, King Arthur's court is graced by a new arrival, Guenevere, whom Merlin has brought from Ireland. Launfal takes a dislike to this new lady, as do many other worthy knights, because of her reputation for promiscuity. King Arthur marries Guenevere and Launfal's fortunes take a sudden turn for the worse. He leaves King Arthur's court when Guenevere shows ill will to him by not giving him a gift at the wedding. Insulted and humiliated, Launfal tells Arthur that he has received word of his father's death, and must return home, and leaves the court, losing his status and income. Arthur wishes him well and sends him off with many costly gifts, accompanied by Arthur's two knight nephews.

Returning to his home town of Caerleon, Launfal requests lodging in the home of his former servant, now the mayor. On hearing that Launfal has left Arthur's service, the mayor demurs, claiming he awaits the return of seven knights currently lodging with him, but when Launfal remarks scornfully to his companions of the manner in which a poor knight is treated, the mayor relents to the point of allowing Launfal and his companions to reside in a chamber beside his orchard, more humble lodgings. Launfal spends all the money that King Arthur gave him before setting out, and soon descends into poverty and debt. Arthur's nephews, having remained with Launfal, take their leave, having become ragged sharing in his poverty; on their return to Arthur, having been requested by Launfal not to reveal his penurious state, they claim they were wearing old garments to hunt before their return, and that Launfal is doing very well. Arthur is very happy to hear this, but the queen is furious, wishing Launfal misery. One Trinity Sunday, the king holds a banquet in Caerleon to which Launfal, because of his poverty, is not invited. The mayor having left to attend the banquet, his daughter offers to let Launfal spend the day with her and dine in her father's hall, but he declines her offer since he has nothing to wear. Instead, he borrows a horse from her and goes for a ride, stopping to rest under a tree in a nearby forest. Two maidens appear and bring him to a lady they call Tryamour, daughter of the King of Olyroun and of Fayrye, whom Launfal finds lying on a bed in a glorious pavilion.

"He fond yn the pavyloun / The kynges doughter of Olyroun, / Dame Tryamour that hyghte; Her fadyr was kyng of Fayrye, / Of Occient, fer and nyghe, / A man of mochell myghte. In the pavyloun he fond a bed of prys / Yheled wyth purpur bys, / That semyle was of syghte. Therinne lay that lady gent / That after Syr Launfal hedde ysent / That lefsom lemede bryght."Laskaya, Anne and Salisbury, Eve (Eds). 1995. Middle English text of "Sir Launfal", lines 277–88.

(He found in the pavilion the daughter of the King of Olyroun, her name was Tryamour and her father was the King of the Otherworld – of the west,Following: Laskaya, Anne and Salisbury, Eve (Eds). 1995. Middle English text of "Sir Launfal", note to line 281. Occient may mean 'west' or 'ocean'. both near and far – a very powerful man. In the tent was a lavishly-adorned and very handsome bed. Lying in it was the beautiful woman who had summoned him.) Tryamour offers Launfal her love and several material gifts: an invisible servant, Gyfre; a horse, Blaunchard; and a bag that will always produce gold coins however many are taken from it, all on the condition that he keeps their relationship a secret from the rest of the world. No one must know of her existence. She tells him she will come to him whenever he is all alone and wishes for her.

Launfal returns to Caerleon. Soon a train of packhorses arrives, bearing all kinds of valuables for him. He uses this new wealth to perform many acts of charity. He also wins in a local tournament, thanks to the horse and banner given him by the lady. A knight of Lombardy, Sir Valentyne, challenges him (on the honour of his beloved lady) to come to Lombardy to fight with him. This section of Thomas Chestre's tale does not derive from Marie de France's Lanval or from the English Sir Landevale, but perhaps from another romance that is now lost. Launfal makes the voyage, and defeats Valentyne, thanks to his invisible servant Gyfre, who picks up his helmet and shield when Valentyne knocks them down. Launfal kills Valentyne and then has to kill many more of the Lombard knights in order to get away.

Launfal's reputation for martial prowess and generosity reaches new heights and word at last reaches King Arthur. Launfal is summoned again by the king, after a long absence, and asked to serve as steward for a long festival beginning at the Feast of St. John. During some revelry at the court, Guenevere offers herself to Launfal. Launfal refuses, Guenevere threatens to ruin his reputation in retaliation by questioning his manhood and Launfal blurts out in his defence that he has a mistress whose ugliest handmaiden would make a better Queen than Guenevere. Guenevere goes to Arthur and accuses Launfal of trying to seduce her and of insulting her as well. Knights are sent to arrest him.

Launfal has gone to his room, but his faerie mistress does not appear and Sir Launfal soon realises why. Tryamour will no longer come to him when he wishes for her since he has given away her existence. Soon, her gifts have disappeared or changed. Now he is brought to trial. Since the jury of his peers all know that the Queen is more likely to have propositioned Launfal than the other way around, they believe Launfal's version of the encounter. However, for his insult he is given a year and a fortnight to produce the beautiful lady as proof of his boast; Guenevere says she is willing to be blinded if he manages to produce such a woman. As the day of the proof progresses, the Queen presses for him to be executed while others express doubt, particularly when two parties of gorgeous women ride up. Finally Tryamour arrives and exculpates Launfal on both counts. She breathes on Guenevere and blinds her. Gyfre, now visible, brings his horse Blaunchard, and Tryamour, Launfal, and her ladies ride away to the island of Olyroun, which in Marie's 12th-century version of the tale is Avalon.Burgess, Glyn S., and Busby, Keith, 1986. The Lais of Marie de France. Penguin Books Limited. Lanval, p 81. Once a year, on a certain day, Launfal returns and his horse may be heard neighing and a knight may joust with him, although he was never seen again in Arthur's land.

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