The Mabinogi is made up of four Branches which tell the stories of three Kindreds. This page is a retelling of the First Branch.
These names for the Branches are not in the mediaeval manuscripts, but they have been in use for over 150 years since 19thC Guest. Branwen is less justified than the others, as her name does not begin the Branch, but is as well established now as the others.
Pwyll prince of Dyfed, decides to go hunting. Separated from his companions, lost in the forest, he sees a stag brought down by strange shining hounds. He beats them off and puts his own hounds to feed on the stag. A horseman appears, owner of the other hounds, who rebukes him for his gross discourtesy. He is Arawn, king of fabled Annwfn. Pwyll undertakes to compensate Arawn for the offence, and win his friendship (alliance).
Arawn shapechanges Pwyll so they can change places. Pwyll lives as 'the man in Arawn's place' for a year (but without making love to 'his' wife the beautiful queen). He fights and conquers Arawn's enemy Hafgan, which is the aim of his contract with Arawn.
Once they both resume their own places, Arawn has some explaining to do to his queen when they are alone together in bed. He concludes Pwyll has shown himself a true friend. Pwyll is acclaimed a hero, 'Head of Annwfn', and the two rulers continue to exchange rich gifts to seal the alliance.
Pwyll decides to accept the challenge of Gorsedd Arberth, a hill behind his court. Its prophecy promises 'wounds or a marvel' if he sits there. As he does so he and his company see a marvellous woman rider on a pale horse go past. Pwyll sends a man and then another after her to find out what she desires, but neither can reach her.
On the third day Pwyll himself chases her but as with his men however fast he rides she stays ahead, though she rides slowly. He begs her to stop. She does so but rebukes him for riding his horse so hard. She identifies herself as Rhiannon, declaring her purpose is to marry Pwyll instead of her existing suitor. He gladly agrees to a wedding in a year's time.
At the feast a good looking princely young man asks Pwyll for a favour, which he generously grants. Rhiannon instantly rebukes his foolish words. For this is Gwawl, the unwanted suitor, who asks for Rhiannon herself! Pwyll is devastated but Rhiannon insists he must agree for honour's sake. However she promises she will free them from Pwyll's words.
At Gwawl's wedding Pwyll follows Rhiannon's instructions, appearing as a beggar asking a small favour, which Gwawl agrees. Pwyll produces a small bag (which Rhiannon had given him) asking for it to be filled with food. But it cannot be filled! Pwyll explains a noble man must step in it and declare it full. Gwawl, urged by Rhiannon, does it, and Pwyll immmediately pulls the bag over his head and ties its strings, trapping him.
Pwyll calls his men in from hiding. They beat Gwawl with sticks, playing 'badger-in-the-bag', until Gwawl surrenders his rights to Rhiannon and his revenge, and pays for the feast as well.
Rhiannon and Pwyll are duly married and journey to Dyfed together.
After jointly ruling Dyfed together in happiness for three years, Rhiannon and Pwyll have no child. The Council of nobles demand Pwyll divorce Rhiannon but he temporises with delay and Rhiannon then gives birth to a son. Six Maids are on duty while she sleeps. But they also sleep, waking to find the child gone.
In great fear they plot to blame Rhiannon. They smear her with puppy blood, then when she wakes accuse her of killing and eating her own baby. With no witness on her side Rhiannon and her counsellors accept her doing penance. She will sit at the gate of Arberth for seven years, telling her crime to travelers, offering to carry them on her back like a horse.
Meanwhile in Gwent, the good lord Teyrnon has a beautiful mare who births a foal every May Eve, which mysteriously disappears. Teyrnon agrees with his wife he will stand vigil to protect the mare, bringing her inside the hall. He sees the new foal born then through the window a dreadful claw reaches for it. Teyrnon slashes it, runs outside but in the dark can see nothing to follow. He discovers a baby left on the step.
He offers the child to his barren wife who gives out it is her own son. They name him Gwri. The boy grows marvellously, adores horses, so his 'mother' gives him the colt born at May Eve. Eventually Teyrnon realises how Gwri resembles Pwyll of Dyfed who he had once served in the past. He and his wife decide to return the boy to Dyfed, and Teyrnon duly takes him there.
At the gates of Narberth Gwri politely refuses Rhiannon's offer of a ride, and they all go into the hall. At the feast Rhiannon sits beside Pwyll as queen, while Teyrnon recounts his tale. All acknowledge the boy as the lost heir. Rhiannon's first words to him that he resolves her pryder, 'loss, anxiety' give him his name - Pryderi. Teyrnon is held in high honour.
Pryderi grows up as a fine prince, becomes ruler of Dyfed when Pwyll dies, and conquers wider territories. He marries Cigfa of Gloyw (Gloucester).