This maiden served the Lady of the Lake, her first cousin, and knew a good deal about magic that Merlin himself had taught her at King Arthur’s court. At that time she was returning to King Arthur’s court on an errand from her lady. When she saw the two knights thus fighting together, she stopped, and she soon recognized Morholt by his coat of arms, and Sir Gawain, too. Then she wondered greatly how this quarrel between them had arisen, for Sir Yvain, to whom she had spoken that very
day, had told her all about how they had become companions, he and Morholt and Sir Gawain.

Then the maiden said to Gawain, “Sir Gawain, what’s the source of this great hatred between you and Sir Morholt?”

“My lady,” he said, “I don’t know, but there’s nobody I hate as much as I do him, and I seek no peace with him until one of us is dead.”

"Truly,” she said, “if you hate him so mortally and he you, but you know of no cause, by my faith, I never heard of such a marvel! ” Then she said to herself, “By my faith, I think they’re under a spell, and I must find out, for it would be a very great pity if they killed each other this way.”

Then she cast her spell and tried to disenchant them. When she had done what she thought would serve this purpose, they both returned to their senses and remembered who they were. They looked at each other; then Sir Gawain threw down his sword and shield, and Morholt did the same.

Post-Vulgate Merlin