Culhwch and Olwen
Kai made a leash
Of Dillus son of Eurei's beard.
Were he alive, thy death he'd be.
And thereupon Kai was wroth, so that the warriors of the Island could scarcely make peace between Kai and Arthur. And henceforth, neither in Arthur's troubles, nor for the slaying of his men, would Kai come forward to his aid for ever after.
Said Arthur, "Which of the marvels is it best for us now to seek?"
"It is best for us to seek Drudwyn, the cub of Greid the son of Eri."
A little while before this, Creiddylad the daughter of Llud Llaw Ereint, and Gwythyr the son of Greidawl, were betrothed. And before she had become his bride, Gwn ap Nudd came and carried her away by force; and Gwythyr the son of Greidawl gathered his host together, and went to fight with Gwyn ap Nudd. But Gwyn overcame him, and captured Greid the son of Eri, and Glinneu the son of Taran, and Gwrgwst Ledlwm, and Dynvarth his son. And he captured Penn the son of Nethawg, and Nwython, and Kyledyr Wyllt his son. And they slew Nwython, and took out his heart, and constrained Kyledyr to eat the heart of his father. And therefrom Kyledyr became mad. When Arthur heard of this, he went to the North, and summoned Gwyn ap Nudd before him, and set free the nobles whom he had put in prison, and made peace between Gwyn ap Nudd and Gwythyr the son of Greidawl. And this was the peace that was made:--that the maiden should remain in her father's house, without advantage to either of them, and that Gwyn ap Nudd and Gwythyr the son of Greidawl should fight for her every first of May, from thenceforth until the day of doom, and that whichever of them should then be conqueror should have the maiden.
And when Arthur had thus reconciled these chieftains, he obtained Mygdwn, Gweddw's horse, and the leash of Cwrs Cant Ewin. And after that Arthur went into Armorica, and with him Mabon the son of Mellt, and Gware Gwallt Euryn, to seek the two dogs of Glythmyr Ledewic. And when he had got them, he went to the West of Ireland, in search of Gwrgi Severi; and Odgar the son of Aedd king of Ireland, went with him. And thence went Arthur into the North, and captured Kyledyr Wyllt; and he went after Yskithyrwyn Benbaedd. And Mabon the son of Mellt came with the two dogs of Glythmyr Ledewic in his hand, and Drudwyn, the cub of Greid the son of Eri. And Arthur went himself to the chase, leading his own dog Cavall. And Kaw, of North Britain, mounted Arthur's mare Llamrei, and was first in the attack. Then Kaw, of North Britain, wielded a mighty axe, and absolutely daring he came valiantly up to the boar, and clave his head in twain. And Kaw took away the tusk. Now the boar was not slain by the dogs that Yspaddaden had mentioned, but by Cavall, Arthur's own dog.
And after Yskithyrwyn Penbaedd was killed, Arthur and his host departed to Gelli Wic in Cornwall. And thence he sent Menw the son of Teirgwaedd to see if the precious things were between the two ears of Twrch Trwyth, since it were useless to encounter him if they were not there. Albeit it was certain where he was, for he had laid waste the third part of Ireland. And Menw went to seek for him, and he met with him in Ireland, in Esgeir Oervel. And Menw took the form of a bird; and he descended upon the top of his lair, and strove to snatch away one of the precious things from him, but he carried away nothing but one of his bristles. And the boar rose up angrily and shook himself so that some of his venom fell upon Menw, and he was never well from that day forward.