Finally, his relations with Guenevere are revealed to Arthur by the sons of King Lot, Gawain, however, taking no part in the disclosure.
As the sentence is about to be carried into execution Lancelot and his kinsmen come to her rescue, but in the fight that ensues many of Arthur's knights, including three of Gawain's brothers, are slain.
Thus converted into an enemy, Gawain urges his uncle to make war on Lancelot, and there follows a desperate struggle between Arthur and the race of Ban.
Gawain (Welwain, Welsh Gwalchmai), Arthur's nephew, who in medieval romance remains the type of knightly courage and chivalry, until his character is degraded in order to exalt that of Lancelot.
The connexion of the story with Arthur and his court brought about a speedy and more important development, the precise steps of which are not yet clear: Perceval became the hero of the Grail quest, in this ousting Gawain, to whom the adventure originally belonged, and the Perceval became merged in the Grail tradition.