Dodinel gave him a great blow with his lance, so that he broke through Tristan's shield and broke the lance on his chest, but he did him no other harm, nor did he move him from the saddle. And Tristan, who was very strong, struck him on top of the helmet so hard that he knocked him to the ground unconscious, so that Dodinel did not know if he was dead or alive. Tristan gave Dodinel no other blow, but that one blow was such that the blood came out of his eyes, his nostrils, and his mouth.

Post-Vulgate Quest for the Holy Grail