Goreu mab Custennin: a Cymric Arthurian Hero (The Best, son of Custennin)

Synonyms:
Cym: The Best, son of Custennin

Goreu mab Custennin is known from a single verse in the Trioedd Ynys Prydain and the tale of Culhwch ac Olwen. In this tale Goreu's father, Custennin had his lands stolen from him and he was reduced to the status of a herdsman for his borther's sheep. Thus, when Cei, Menw and Gwrhyr and Culhwch come to Yspydadden's lands they spy a Llys upon a rocky outcrop and before this an enormous flock of sheep that seemed boundless and without end. Atop a mound, within the confines of the flock there sat a giant figure who wore a rough cloak made of sheepskin and whose right hand caressed the shaggy coat of an enormous mastiff, larger than a full-grown horse. Not a little afraid, the three hosemen paused, until Menw promised that he could subdue the mastiff with a spell. So the companions made their way forwards until they could address the giant, who announced himself as Custennin, son of Dyfnedig and brother of Yspydadden. The selfsame Yspydadden who had disposessed him of his lands and his posessions. For their part the four companions told Custennin who they were and what their mission was. Cusatennin warned them not to progress further for none who did so ever returned. Regardless the four men made it plain they would continue and they bade Custennin farewell; though as they did so Culhwch gifted Custenin a ring as a gift. The ring was too large to fit on Custennin's finger so he placed it within his glove instead. That evening, as the herdsman went home to his wife he gave her his ring to keep and she managed to wheelde out of him that he had been gifted the ring by Culhwch son of Cilydd, son of Celyddon by Goleuddydd the daughter of Anlawdd. Hearing this she felt torn between the joy that her nephew was coming to her and sorrow that anyone who sought the hand of Olwen never returned from the quest. Nonetheless they went out towards the edge of Custennin's dwelling and when she heard the four strangers approach she ran to greet them. They were ushered into the couples' home where they were served meat and drink. At the end of the evening the woman opened a stone chest that lay before the chimney corner and from this there sprang a golden-haired youth. Gwrhyr commented that it was a shame to hide such a youth from the eyes of the world whereupon the woman responded that the boy was simply a remnant, for three and twenty other sons had she bourne and all of them had been slain by Yspadadden and she feared that the same fate would befall this one. Cai promised that he would protect the boy where he only allowd to go with the four travellers. That no harm could or would befall him unless Cai was slain alongside him. They take the child with them to the Llys of Gernach Gwar where, upon interrogation by the porter, and they describe their craft. Cei, Bedwyr and the child are allowed entry; Cei for his skill at burnishing swords, Bedwyr for his skill with a spear that could draw blood from the wind and Custennin's son as their apprentice. Custennin's son fights his way through the three courtyards of Gwrnach's Llys and for this was he named Goreu (the Best). At the final act of the tale, the marriage feast of Culhwch and Olwen Goreu takes Ysbydadden by the hair and severs his head from his body. This act avenges the belittling of this father and the murder of his brothers.

Though the mother of Goreu is never named, though from the genealogies of Brut Dingestow it seems that she is the sister of Eigr ferch Amlawdd Wledig (Arthur's mother) and thus Goreu is a cousin of Arthur himself. This is relevant in terms of Triad 52 of the Trioedd Ynys Prydein where in the addendum to the triad where Arthur is described as the most exalted prisoner of the Island of Britain who was held three nights in the keep of Oeth and Anoeth and three nights imprisoned by Gwen Pendragon and three nights in the enchanted prison under the Stone of Echymeint. In each case he was freed by Goreu mab Custennin.

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