Note: I originally wrote a version of this story as a sort of interlude in my historical novel Griffri, set in twelfth century Wales. The tale  is written in the style and set in the milieu of the early Welsh tales of the Mabinogi, but it draws on the extraordinary Algonquian myth, The Beaver Medicine Legend, and also borrows something from other sources including the first known written story, The Epic of Gilgamesh.  A full text of a revised version was first published in 2006 with the title The Story of the Afanc King & the Sons of Teyrnon as a limited edition from Gwasg Gregynog, with linoprints by the Sara Philpott (http://www.gregynogpress.co.uk/)
 

When Teyrnon Twrf Liant was ruler over Gwent Iscoed, it happened that after a long time without children his wife became pregnant.
     Teyrnon’s wife said to him, “This is god’s reward for restoring the foundling child, Gwri Wallt Eurin, to his true parents, Pwyll and Rhiannon.”
     Teyrnon remembered the time, as returning the child had almost broken his heart. He said, “When this child is born we will name it after Gwri Wallt Eurin.”
     But Teyrnon’s wife gave birth to twins.  Teyrnon was filled with love for his sons and decided that one would be called Gwri and the other Eurin.
     Gwri and Eurin grew to manhood and they became admired princes.  They were close friends, alike in all things except one, and this was that Gwri conceived that his father Teyrnon showed greater love and favour to his brother Eurin than to himself.

One day the brothers went out to hunt.  Gwri had a spear of steel and Eurin’s was of gold.  Gwri’s bow was of elm and Eurin’s was of yew.
     Chasing the boar, they became lost and came to a valley they had never seen before.  Still in pursuit, they plunged into the trees and came to the shore of a lake and in its centre there was an island.
      “I can see the boar swimming,” Gwri said.
     Eurin looked the way his brother had pointed.
      “It has climbed onto that island,” Gwri said.
     But Eurin had not seen it.
     “Let us cross to the island,” Gwri said.
     And the brothers cut down a tree and hollowed it, and, using the blades of their spears, paddled across. They paddled for a day and a night and in the morning they walked onto the island.
     Eurin set out after the boar, saying, “If we catch him people will call this island Ynys y Twrch because this was where the boar was killed.”
      “They had better call it Ynys Eurin, then,” Gwri said.
     At that, Eurin turned, dropping his weapons, and saw Gwri approaching with his sword raised.
      “My other self!” Eurin cried.  “What’s this?”
     But Gwri said nothing.
     Eurin tore off a bough of rowan to defend himself and that was how they fought, with sword and branch.  Gwri swung his sword down and instantly the branch was severed.  The blade struck Eurin’s head, and so he fell.
     At that moment Gwri knew what he had done and he was filled with grief and terror.  He gathered the weapons and fled.  But as he paddled across the lake some of his terror left him and he said, “I will tell nobody about this.”
     Reaching the shore, he took up Eurin’s golden spear and yew bow. He sank the boat and returned to his father’s court.  

Teyrnon and all the court were pleased at the return of the king’s son, but because he carried the golden spear and the bow of yew and had left his own weapons in the boat, they thought that he was Eurin.
     While Gwri embraced his mother, Teyrnon said, “Eurin, where is your brother?”
      “Father,” Gwri said, “I lost him among the trees, then I heard a cry and ran to him.  I came to a lake and Gwri was wrestling with the boar in the water and they went under.  They returned to the surface.  I searched for three days but found nothing.”
     Teyrnon’s grief was great and he could not speak. The whole country was so concerned at his condition that they neglected Gwri’s story.  For three years Teyrnon was silent, and no richness of the land nor the love of his people nor the songs of his poets could bring him from his affliction.  After that, he died and Gwri called Eurin became ruler.  The new king made a wise match, marrying the woman Indeg who had been purposed for his brother.

But Eurin had not died. Although the sword had cut through the rowan bough, its force had been weakened.  Three days and nights he lay on the shore after Gwri had left him. Then he woke and found the broken bough in his hands and the wound on his head.
     The island had many animals and small trees, though there were no people.  And so he lived by hunting that summer.
     One day Eurin walked to the furthest shore of the island, and there he saw a wooden city.   The peculiarity of this city was this: that part of it was built on the land and part of it was built on the water.
     While he looked, Eurin saw a strange creature approaching him.  The creature was less than half Eurin’s height and it had sleek fur and a long tail and yellow fangs, but it had the hands and face of a man, and a man’s voice.
      “My father invites you into his city,” the animal said.
     Eurin walked with the creature through the city gates.
     Inside, he went through many halls that were under the earth and many that were over the water.  The animal presented him to his father, who was the Afanc King, and all his family.
     The king was larger than the others and wore a torc of piped gold, and his fur was silvered.
     The Afanc King entertained his guest with food and music.  After the meal, Eurin told the story of his cruel treatment to the king, who said,
      “Eurin, live here with me, and my family and I will teach you good and useful things.”
     Eurin accepted this and among these creatures he was the first man to learn beekeeping and the making of mead, and from the Afanc King himself he learned magic.   
     So for three years Eurin was happy, but then he discovered, by the art the Afanc King had taught him, of his father’s death and of what else had happened at Teyrnon’s court, and he longed for his birthright and his country.
     Eurin told these things to the king.
     The Afanc King was thoughtful and then said:
      “Eurin, I can bring about what you want.  Every year my bees visit your country to gather pollen.  Next spring, one of them can carry a message to bring your brother here.  But if you leave my country you may never return.”
     Eurin said he would do this, and though the Afanc King was sad, he allowed it.  

Gwri called Eurin was king of Gwent Iscoed and his mother, his wife Indeg, and the people were surprised that his rule was less wise than his father’s.
     In truth, Gwri often thought of his brother, and of Teyrnon’s grieving for the son he had thought was Gwri, and these thoughts burdened him.
     One night, when Gwri and Indeg were asleep, a bee flew into their room.  It settled in Indeg’s hair and there it buzzed gently.
     At first light, it flew away and Indeg woke up suddenly with a cry.
      “Eurin,” she said.  “I had a strange dream.  I dreamt I was standing on the shore of the lake you spoke of.”
      “What lake?” Gwri said, though he knew well enough.
      “Where Gwri fought the boar,” she said.  “I looked across the water and I could see an island.  Why are you staring?  There was a ripple in the lake and a man walked up out of the water, as if he had walked from the island.  It was Gwri.”
     Gwri was angry and shook Indeg by the shoulders, but he saw she was afraid and his anger left him.  He told her to go on.
      “He had a strange branch in either hand,” she said, “ and on his head there was a wound.  And that was my dream.”
     Gwri hid his disquiet, but decided to go back to the island and see his brother’s bones on the shore so that his mind would be soothed.

So Gwri went out one day, saying that he would hunt alone and he made himself a boat of skins and he searched for the lake.
     At length he saw a boar, which turned ran into the trees.  Gwri followed and soon he was in the strange valley again.
     When he came to the lake, Gwri put his boat in the water and went to the island.  He arrived quickly, because even when he rested, the boat still moved as if drawn by a charm.
     On the shore, he went to the place where he had struck his brother.  He found no remains.
     Eurin had been watching from a thicket nearby and when he saw Gwri’s fear, by his art he took the form of a huge boar and rushed out.  Gwri fled into the water but the boar followed him and they went under the surface, and that was the end of Gwri.  Presently the boar returned alone and resumed the form of Eurin.
     So Gwri, in his invention, had foreseen the manner of his own death.
     Eurin said goodbye to the Afanc King and his people and took as a gift a sapling rowan because that was the tree that had saved his life.  He went back to his father’s country, and he never saw the island or the city or the Afanc King again.
 
The true Eurin was accepted in Gwent Iscoed and told no one what had happened.  He ruled well and taught his people how to make mead and the country came to know of his skill in magic.  He planted the rowan, and that was how it came into this country. Eurin it was who showed the tree’s power to ward off ill-doing.
     Because of all these things Indeg grew suspicious, and asked him about his solitary hunt.  Then Eurin told her his story.  At first Indeg would not believe him but then he parted his hair and showed her the scar where Gwri’s sword had wounded him.  And, she remembered her dream and saw that the strange branches were of rowan. She remembered how her husband had stared and then grown angry when she told him about the dream, and she had to believe.
      “Are you angry that I have tricked you?” Eurin said.
      “No,” she said, “You are truly yourself.  It was Gwri who tricked me.”
     After that Eurin ruled many years and they lived happily.