It is in keeping with the mythological character of Arthur that the early Welsh tales recorded of him are of a different nature from those which swell the pseudo-histories of Nennius[437] and of Geoffrey of Monmouth. We hear nothing of that subjugation of the countries of Western Europe which fills so large a part in the two books of the _Historia Britonum_ which Geoffrey has devoted to him.[438] Conqueror he is, but his conquests are not in any land known to geographers. It is against Hades, and not against Rome, that he achieves his highest triumphs. This is the true history of King Arthur, and we may read more fragments and snatches of it in two prose-tales preserved in the Red Book of Hergest. Both these tales date, in the actual form in which they have come down to us, from the twelfth century. But, in each of them, the writer seems to be stretching out his hands to gather in the dying traditions of a very remote past. When a Welsh man-at-arms named Rhonabwy lay down, one night, to sleep upon a yellow calf-skin, the only furniture in a noisome hut, in which he had taken shelter, that was comparatively free from vermin, he had the vision which is related in the tale called “The Dream of Rhonabwy”.[439] He thought that he was travelling with his companions towards the Severn, when they heard a rushing noise behind them, and, looking back, saw a gigantic rider upon a monstrous horse. So terrible was the horseman’s appearance that they all started to run from him. But their running was of no avail, for every time the horse drew in its breath, it sucked them back to its very chest, only, however, to fling them forward as it breathed out again. In despair they fell down and besought their pursuer’s mercy. He granted it, asked their names, and told them, in return, his own. He was known as Iddawc the Agitator of Britain; for it was he who, in his love of war, had purposely precipitated the Battle of Camlan. Arthur had sent him to reason with Medrawt; but though Arthur had charged him with the fairest sayings he could think of, Iddawc translated them into the harshest he could devise. But he had done seven years’ penance, and had been forgiven, and was now riding to Arthur’s camp. Thither he insisted upon taking Rhonabwy and his companions.