Sword of the Valiant: The Legend of Sir Gawain and the Green Knight (1984)

Gawain was a squire in King Arthur's court when the Green Knight burst in and offered to play a game with a brave knight. No knights stand to defend their king's honor. Except for the valiant Gawain. After being quickly knighted Gawain plays the game, but learns that it's all a trick, and he has lost. But the Green Knight shows mercy, letting Gawain grow a year older before having to face the consequences. Gawain journeys across the land, learning about life, saving damsels, and solving the Green Knight's riddle.