Sir Melligrance is an antagonist in the Arthurian legends, he is a treacherous Knight of the Round Table who lusted after Queen Guinevere despite her being married to Arthur, and he was power-hungry and ruthless, he abducted Guinevere when she was out looking for Sir Lancelot, and Melligrance was about to kill her knights but when she begged him to he spared them.
Melligrance threatened to kill her if she didn't come to his castle and he dragged Guinevere off to his castle and held her hostage. Sir Lancelot met one of Guinevere's terrified maids fleeing from the abduction but she told Lancelot of Melligrance's betrayal, and Lancelot got furious and rushed to save Guinevere.
In what has now become the staple "damsel in distress story" Lancelot broke into the castle and fought the evil Sir Melligrance, it was an equal duel of wills until Lancelot threw Sir Melligrance down on his back and threatened to kill the treacherous dog. Sir Melligrance was a coward and begged for mercy, and to his astonishment Queen Guinevere also asked for mercy because Sir Melligrance had spared her knights. She asked Sir Lancelot to forgive Sir Melligrance and he decided to, but vowed if Sir Melligrance touched Queen Guinevere again he would kill him. Sir Melligrance may have been killed at Camlaan, if he didn't desert King Arthur after.