The dream of Rhonabwy
Then they beheld another troop coming towards the ford, and these from their horses' chests upwards were whiter than the lily, and below blacker than jet. And they saw one of these knights go before the rest, and spur his horse into the ford in such a manner that the water dashed over Arthur and the Bishop, and those holding counsel with them, so that they were as wet as if they had been drenched in the river. And as he turned the head of his horse, the youth who stood before Arthur struck the horse over the nostrils with his sheathed sword, so that, had it been with the bare blade, it would have been a marvel if the bone had not been wounded as well as the flesh. And the knight drew his sword half out of the scabbard, and asked of him, "Wherefore didst thou strike my horse? Whether was it in insult or in counsel unto me?"
"Thou dost indeed lack counsel. What madness caused thee to ride so furiously as to dash the water of the ford over Arthur, and the consecrated Bishop, and their counsellors, so that they were as wet as if they had been dragged out of the river?"
"As counsel then will I take it."
So he turned his horse's head round towards his army.
"Iddawc," said Rhonabwy, "who was yonder knight?"
"The most eloquent and the wisest youth that is in this island; Adaon, the son of Taliesin."
"Who was the man that struck his horse?"
"A youth of froward nature; Elphin, the son of Gwyddno."
Then spake a tall and stately man, of noble and flowing speech, saying that it was a marvel that so vast a host should be assembled in so narrow a space, and that it was a still greater marvel that those should be there at that time who had promised to be by mid-day in the battle of Badon, fighting with Osla Gyllellvawr.
"Whether thou mayest choose to proceed or not, I will proceed."
"Thou sayest well," said Arthur, "and we will go altogether."
"Iddawc," said Rhonabwy, "who was the man who spoke so marvellously unto Arthur erewhile?"
"A man who may speak as boldly as he listeth, Caradawc Vreichvras, the son of Llyr Marini, his chief counsellor and his cousin."
Then Iddawc took Rhonabwy behind him on his horse, and that mighty host moved forward, each troop in its order, towards Cevndigoll. And when they came to the middle of the ford of the Severn, Iddawc turned his horse's head, and Rhonabwy looked along the valley of the Severn. And he beheld two fair troops coming towards the ford. One troop there came of brilliant white, whereof every one of the men had a scarf of white satin with jet-black borders. And the knees and the tops of the shoulders of their horses were jet-black, though they were of a pure white in every other part. And their banners were pure white, with black points to them all.