As soon as sleep had come upon his eyes, it seemed to him that he was journeying with his companions across the plain of Argyngroeg, and he thought that he went towards Rhyd y Groes on the Severn. As he journeyed, he heard a mighty noise, the like whereof heard he never before; and looking behind him, he beheld a youth with yellow curling hair, and with his beard newly trimmed, mounted on a chesnut horse, whereof the legs were grey from the top of the forelegs, and from the bend of the hindlegs downwards. And the rider wore a coat of yellow satin sewn with green silk, and on his thigh was a gold-hilted sword, with a scabbard of new leather of Cordova, belted with the skin of the deer, and clasped with gold. And over this was a scarf of yellow satin wrought with green silk, the borders whereof were likewise green. And the green of the caparison of the horse, and of his rider, was as green as the leaves of the fir tree, and the yellow was as yellow as the blossom of the broom. So fierce was the aspect of the knight, that fear seized upon them, and they began to flee. And the knight pursued them. And when the horse breathed forth, the men became distant from him, and when he drew in his breath, they were drawn near to him, even to the horse's chest. And when he had overtaken them, they besought his mercy. "You have it gladly!" said he, "fear nought." "Ha, chieftain, since thou hast mercy upon me, tell me also who thou art," said Rhonabwy. "I will not conceal my lineage from thee. I am Iddawc the son of Mynyo, yet not by my name, but by my nickname am I best known." "And wilt thou tell us what thy nickname is?" "I will tell you; it is Iddawc Cordd Prydain." "Ha, chieftain," said Rhonabwy, "why art thou called thus?" "I will tell thee. I was one of the messengers between Arthur and Medrawd his nephew, at the battle of Camlan; and I was then a reckless youth, and through my desire for battle, I kindled strife between them, and stirred up wrath, when I was sent by Arthur the Emperor to reason with Medrawd, and to shew him, that he was his foster-father and his uncle, and to seek for peace, lest the sons of the Kings of the Island of Britain, and of the nobles, should be slain. And whereas Arthur charged me with the fairest sayings he could think of, I uttered unto Medrawd the harshest I could devise. And therefore am I called Iddawc Cordd Prydain, for from this did the battle of Camlan ensue. And three nights before the end of the battle of Camlan I left them, and went to the Llech Las in North Britain to do penance. And there I remained doing penance seven years, and after that I gained pardon."