The Dream of Rhonabwy
The tale begins with Madawc, son of Maredudd and ruler of Powys. His brother Iorwerth is sorrowful that he doesn't enjoy the same power. Madawc offers to make him master of the household, with horses, arms and honour, but Iorwerth refuses.
Iorwerth travels to Loegria, where he slays the inhabitants and takes prisoners. Appalled, Madawc agrees to place 300 men across three posts in Powys - Aber Ceirawc, Allictwn Ver and Rhyd Wilure - to look for him.
One of the men is a knight called Rhonabwy. He, Kynwrig Vrychgoch and Cadwgan Vras agree to assemble in the house of Heilyn Goch. Upon entering the house they find the floor slippery and covered in water. On one side they see a hag making a fire.
The men are seated, and ask the hag where the people of the house are. She mutters something, whereupon the residents arrive: a curly-haired man and a pale, slender woman, both carrying wood. They tend to the fire, and the woman gives the men bread, cheese, milk and water.
A storm begins, and the men agree to stay the night, although their couch is uncomfortable and the house is plagued by rats. Rhonabwy decides to sleep instead on a yellow calf-skin stretched out on the floor.
He dreams of journeying with his companions across the plain of Argyngroeg, towards Rhyd y Groes on the Severn. He sees a youth riding a chestnut horse. Fearful, the youth begins to flee, but the knight catches up with him. The youth reveals his name, Iddawc Cordd Prydain, and says he had been a messenger for Arthur and his nephew Medrawd (named Medrod or Mordred elsewhere).
Iddawc had stirred up animosity between Arthur and Medrawd, which resulted in the battle of Camlan. Three nights before the battle's end, he went to the Llech Las in north Britain in penance, remaining for seven years until his pardon.
Then Rhonabwy and Iddawc hear a mighty sound, and see a ruddy youth on horseback. The youth demands a share of Iddawc's companions, which he refuses. The youth departs and Iddawc identifies him as Rhuvawn Pebyr, son of Prince Deorthach.
They continue to Rhyd y Groes, where they see tents and encampments. On a nearby island sits Arthur, along with Bedwini the bishop, the knight Gwarthegyd and a tall youth. Iddawc and the men approach Arthur. Iddawc points out to Rhonabwy a ring with a stone on the hand of Arthur, which he says will enable him to remember the encounter.
The men then see troops, coloured red, approaching. Another set of troops also arrives, this time black and white. One of these knights enters the water, drenching Arthur and the people with him. The tall youth, in retribution, strikes the knight's horse with his sheathed sword. The knight is identified as Adaon, the son of Taliesin; the tall youth as Elphin, son of Gwyddno.
Iddawc and Rhonabwy follow Arthur's army towards Cevndigoll where, in the valley of the Severn, they see two sets of troops clad in pure white approaching the ford. They are men from Norway, whose prince is a cousin of Arthur. Behind them are more troops, from Denmark, led by Edeyrn son of Nudd.
Arthur and his men dismount below Caer Badou. Eirynwych Amheibyn, Arthur's servant, lays out a magical carpet that conceals anyone upon it. Arthur and Owain play chess, with the former seated on the carpet.
After their game they see a white and red tent, from which a young page emerges bearing a sword. He approaches and speaks to Owain, but is unable to see Arthur. The page tells Owain that the young pages and attendants torment his ravens, and Owain asks if Arthur can forbid them from doing so. Arthur instructs Owain to keep playing.
Similar scenes take place with two young men, who in turn approach and salute Owain, but once again ignore Arthur. The men both mention the ravens, and Owain asks Arthur if he should outlaw his attendants from harassing the ravens. Arthur keeps playing.
Owain tells the last youth, Gwes son of Rheged, whose ravens had been killed, that he should return to the ravens and lift his banner. The young man does so, and the ravens arise once again. The birds attack the men who had tormented them, carrying them into the air and tearing them apart.
Two knights separately ride towards Owain and Arthur. In turn, they tell Arthur that the ravens of Owain are slaying his men. Arthur tells Owain to forbid his ravens, but both times Owain instructs his master to continue playing chess.
They finish their game and begin another. A knight approaches, telling Arthur that the ravens had slain his household and the sons of the chief men of the island. Arthur tells Owain to forbid the birds, then crushes the chess pieces until they are dust. Owain orders Gwes to lower his banner, and all is peaceful.
Rhonabwy asks Iddawc the identities of the first three men to tell Owain of his suffering ravens. "They were men who grieved that Owain should suffer loss, his fellow-chieftains and companions," he replies. "Selyv the son of Kynan Garwyn of Powys, Gwgawn Gleddyvrudd, and Gwres the son of Rheged, he who bears the banner in the day of battle and strife."
He then asks Iddawc who were the last three men who told Arthur that the men were being slaughtered. "The best and bravest of men: Blathaon the son of Mawrheth, Rhuvawn Pebyr the son of Prince Deorthach, and Hyveidd Unllenn."
From Osla Gyllellvawr come 24 knights seeking a truce from Arthur for six weeks. Arthur arises to take counsel from his men. They talk, and bards recite verses in praise of the king.
Then come 24 donkeys laden with silver and gold, each led by a man in tribute to Arthur from the Greek islands. Kadyriaith, son of Saidi, says a truce should be granted to Osla Gyllellvawr for six weeks, and the donkeys and gifts might be given to the bards. This is agreed to.
The knight Kai arises, saying "Whosoever will follow Arthur, let him be with him to-night in Cornwall, and whosoever will not, let him be opposed to Arthur even during the truce." A celebration ensues, during which Rhonabwy wakes. He finds he has been upon the calf skin for three days and nights.