Sir Meleagant probably became a Knight of King Arthur’s Round Table at a young age, by virtue of his being the son of good King Bagdemagus. He often attended the tournaments, including Dame Lyonors' at Castle Dangerous, where he defeated Sir Gareth, and King Galehaut's Sorelais meeting, where Sir Sauseyse was employed by his father to beat him quickly and get him to safety off the field. Meleagant was, however, not the most popular of knights at court and appears to have grown resentful of the respect earned by others.

Sir Meleagant harboured a secret love for Queen Guinevere and this was to be his undoing. His feelings were first suspected when he had a ferocious clash with Sir Lamorak concerning the relative beauty of Guinevere and her sister-in-law, Morgause. The two knights fought for some time before Sir Bleoberis was able to intervene and bring them to their senses. Eventually, Meleagant was unable to suppress his burning passions and he was forced to resort to drastic and villainous actions to get what he wanted.

It was early May and Queen Guinevere was staying at the Royal palace in London from which she decided to take a small unarmed party out a-Maying (gathering flowers, particularly May blossom, and generally celebrating the coming of Summer). They went out into the fields of what is now Westminster; but Sir Meleagant had set an ambush there for the Queen. With his band of ruffians, he attacked, wounded several of the Queen’s knights and made off with her, back to his own kingdom of the Summer Country. Only a single child managed to escape and ran with the terrible news to Guinevere’s lover, Sir Lancelot. The great knight started out after them immediately, but some of Meleagant’s archers shot his horse from under him and he was forced to continue in a humble cart: a highly embarrassing mode of transport, but the only one he could get hold of at such short notice. By the time Lancelot caught up with them, Meleagant had his unhappy captive safely locked up within his castle. He already tried to force himself upon the lady but had been pulled away by his aging father. Attempts at rescue by Sirs Kay and Gawain had failed miserably. However, Meleagant was terrified of Lancelot’s wrath and quickly yielded up the Queen rather than face having to fight the greatest of all knights. They all spent the night at the castle, but Lancelot could not bear to be so near and yet so far from his lover and broke into the Queen’s bedchamber, wounding his hand in the process. Meleagant thus discovered her in the morning amongst blood-stained sheets and immediately accused her of using one of her wounded followers for sexual gratification. He, however, had more important concerns on his mind. Lancelot had arranged for a trial by combat, which Meleagant was eager to avoid. So he took his opponent on a grand tour of his castle, whereupon, in a particular room, a trap door opened up, throwing Lancelot into a deep dungeon. Luckily, the knight’s gaoler was Maleagant’s pretty young sister, easily seduced into letting him go in return for a passionate kiss. Lancelot was thus still able to turn up to the scheduled fight. When the battle began, he quickly gained the upper hand and Maleagant tried to surrender. Repulsed by the knight’s advances, Guinevere, however, wanted him dead. So Lancelot refused to accept his capitulation. Meleagant similarly refused to continue the fight unless Lancelot tied his left hand behind his back. The great knight agreed but was still able to quickly cleave Meleagant’s head in two.

Meleagant’s tale is an ancient one and, in origin, he appears to have been an historical King of Glastening called Melwas.