Then he ran King Rion down, wielding his sword with both hands, for he was filled with wrath, and he meant to strike him over the head. But King Rion stepped aside, for he had seen the stroke coming at full speed; even so, King Arthur hit him on the helmet and cut him down across the nose, and, as the sword went downward, he struck his warhorse in front of the saddlebow and sliced all the way through its neck, and King Rion fell to the ground.

Vulgate Merlin