Merlin came there with the banner with the dragon that spewed fire and flame from its throat, and he had driven through where the press was heaviest. And when King Rion’s men saw the fire and the great wonder of the dragon, they grew frightened and yielded their ground. The two kings whom they had run down stood quietly where they were, and Merlin came to them and gave each one a good, strong, and fast horse, for there were many strays in the thick of battle; they were eager to be mounted at once.

Vulgate Merlin