Seeing this amazing adventure, Perceval scaled the mountain as fast as he could. But the swiftfooted lion had already passed him and had begun to attack the serpent before Perceval caught up. As soon as he reached the top of the rock and surveyed the two animals, he decided to help the lion because it is a more respectable animal and of a nobler species than the serpent. He drew his sword and raised his shield to protect his face from fire. Then he turned to the serpent and landed a heavy blow between its eyes. The serpent spit fire and flames, burning Perceval’s shield and the front of his hauberk. The serpent would have done more damage, but Perceval was quick and agile enough to catch the flames as one would firebrands, avoiding direct hits from them and minimizing the fire’s effect. But when he saw the flames, Perceval was apprehensive that they might be laced with venom. Nonetheless, he continued to charge the serpent and strike heavy blows wherever he could, finally landing a blow on the very spot that had suffered the first strike. Perceval wielded a very reliable and flexible sword, which slid easily into the serpent’s head. Once the skin had been pierced, the bones offered little resistance and the serpent fell down dead.

Vulgate Quest for the Holy Grail