And as soon as he had drawn it from its scabbard, it cast a very bright light, as if it were a blaze of fire, and he covered himself with his shield and struck a blow on the giant, before he could shield himself, right on the head. And when he saw the blow coming, he threw his shield up against it, for he mightily feared a blow from the sword he had seen glowing and throwing off fire; he well knew that it was of very great worth. He raised his bludgeon against it, and King Arthur hit it so hard with both hands that it flew into pieces, although it was bound in iron. The blow was so strong and powerfully struck, and it fell on his shield and split it as far as the boss, and thrusting the sword back away from himself he sent King Rion staggering; he was upset for having lost his bludgeon.

Vulgate Merlin