The Tribe of Goronwy Pebyr of Penllyn, who refused to stand instead of their lord to receive the poisoned dart from Llew Llaw Gyffes, by Llech Goronwy, at Blaen Cynvael, in Ardudwy. 
After being nursed back to full health, Lleu Llaw Gyffes wanted justice; so the story goes:
"........they mustered Gwynedd and made for Ardudwy. Gwydion went in front, and made for Mur Castell. Blodeuedd, when she heard that they were on their way, took her maidens with her and made for the mountain, across the River Cynfael, making for a court that was up the mountain. And so frightened were they, that they could not walk without facing backwards. Then, before they knew it, they fell into a lake and all drowned except Blodeuedd herself. And then Gwydion overtook her, and said:
'I will not kill you. What I am going to do is even worse,' he said 'that is, I will release you in the shape of a bird. Because of the shame that you have wrought upon Lleu Llaw Gyffes, you will not dare to show your face ever again in the light of day ever again, and that will be because of enmity between you and all birds. It will be in their nature to harass you and despise you wherever they find you. And you will not loose your name - that will always be "Bloddeuwedd". 
Goronwy fled, making for Penllyn, which is a commot on the borders of Llyn Tegid, or Bala Lake.
He sent out envoys to Lleu offering him terms, "either land or territory or gold or silver."
Lleu refused Gorowy's offer of terms and sent back the following message: "Here is the least I'll accept from him: going to the place where I was, when he cast the spear, with me in the place where he was. And let me cast a spear at him. That is the least I will accept from him."
Gorowy then asked his nobles and his warband if there was anyone one that would take this blow for him.
They refused and because of this refusal to endure the taking of a single blow on behalf of their lord, they are remembered in a Triad as one of the Three Disloyal Warbands:"The Tribe of Goronwy Pebyr of Penllyn, who refused to stand instead of their lord to receive the poisoned dart from Llew Llaw Gyffes, by Llech Goronwy, at Blaen Cynvael, in Ardudwy. And the Tribe of Gwrgi and Peredur, who deserted their lords in Caer Greu, where there was an appointment for battle next morning against Eda Glinmawr,and they were both slain. And the third, the Tribe of Alan Vyrgan who returned back by stealth from their lord, leaving him and his servants going to Camlan, where he was slain."
....And with that they both went to the banks of Afon Cynfael. And once there Goronwy Pebyr stood where Lleu had been when he'd been struck and Lleu stood where the other had been. And then Goronwy said unto Lleu: 'Lord,' said he, 'since it was from the deceit of a woman that I did unto you as I did, I implore you, before god, to allow me to set that flat stone that I see on the riverbank between myself and the blow.'
Lleu did not refuse this and so Goronwy took the stone and placed between himself and the blow. Then Lleu cast his spear at Goronwy and it pierced the stone and went through, and it went through Goronwy as well and broke his back.
And there Goronwy Pebyr was slain, and there lies the stone upon the banks of Afon Cynfael in Ardudwy, with the hole still through it. Which is why, until this day, it is called Llech Goronwy.
A second time did Lleu Llaw Gyffes take possession of his land, and he governed it prosperously. And as the story-tellers relate he became, after this, the lord of Gwynedd. Thus ends this branch of the Mabinogi. 
Lleu’s retribution swiftly brings the tale of Math son of Mathonwy and indeed the Four Branches of the Mabinogi, in its current form, to an end.
If, as already suggested, the Mabinogi was originally Tales pertaining to the family of Mabon, ending with Pryderi’s death, then the story of Lleu may well have been a later appendage, the reference to the Triad The Three Disloyal Warbands at the end of this branch suggests an oral variant of the tale was in existence when the redactor wrote Math son of Mathonwy in its extant version. 
At first glance this would appear to be a straight forward onomastic tale to account for Llech Goronwy in Cwm Cynfael, just south from Ffestiniog and the sites of Llyn y Morwynion, (Lake of the Maidens) and Mur Y Castell, (Tomen-y-Mur ) in Ardudwy. Not far from here is also the claimed burial place of Pryderi at Maentwrog.
Tomen-y-Mur was used by the Romans as a marching camp on the Sarn Helen Roman road, probably named after “Elen of the Hosts” running for about 160 miles from Aberconwy in the north to Carmarthen in the south. Elen of the Hosts, also known as Elen of the Ways, She is Protectress of the Pathways; guardian of all who journey, patron of travellers. Elen is best known from Welsh legend as Elen Luyddogg in the Mabinogion in “The Dream of Macsen Wledig”; Elen is discovered by Mascen in a dream. Her beauty was compared with that of the Sun.
In Britain the was a Cult of St Helen predominantly in the North country, where many churches are dedicated to her, and more 'holy' wells were named for Helen than for any other non-biblical female saint. 
Tomen-y-Mur was Lleu’s castle and it is while he was away visiting Math in Arfon that lonely Blodeuedd had met Goronwy while he was out hunting. Blodeuedd was created by Gwydion and Math as a companion for Lleu as his mother Aranrhod had cursed him not to have a wife of this race. Blodeuedd was created for Lleu’s sexual satisfaction, (some have called her a sex beast) therefore it can be little surprise that she took a lover while on her own – it was her sole purpose in life.
Llyn y Morwynion (Lake of the Maidens), less than a mile from Tŷ Nant y Beddau, is where the serving maids of Blodeuedd fell while being pursued by Gwydion, the sorcerer. Blodeuedd flees with her maidens from the fort at Tomen-y-Mur but because they were constantly looking back at their pursuers, they all fall headlong into the lake and are drowned, all except Blodeuedd who is transformed into an owl by Gwydion and from then on known as Bloddeuwedd (Owl).
It would appear unlikely that the tale of Goronwy has been added to the conclusion of the Fourth Branch of the Mabinogi purely as a onomastic tale claiming to account for the name of the stone found in Cwm Cynfal, although the Mabinogi claimed the stone was still there on the banks of the Cynfal.
In 1934, Frank Ward discovered a stone in the bed of the river Cynfal, measuring some forty inches by thirty inches, with a hole straight through it, about an inch in diameter. The stone had apparently been washed downstream by this time from its earlier position in the Ceunant Coch, where a woman who had lived in a farmhouse called ‘Llech Ronw’ nearby, recalled having seen it. She added that a about 150 yards away was a fallen standing-stone which was believed to mark the site of the grave of Goronwy Pebyr (Bedd Goronwy). A later account confirmed the same story. 
A few years ago it was claimed the rock was found again, not on the banks of the river Cynfael but on one of its tributaries. The rock is unusual; a man sized flat stone with a hole at about what would be heart-height.
The farm, on whose land the stone is found, is called "Bryn Saeth" (the hill of the arrow), a farm nearby is called Llech Goronwy (Goronwy's Stone), and, making a triangle with those two a third farm is called "Bryn Gyfergyd" (the hill of the blow). 
The stone can still be seen today as shown in the pictures, however whether this is the original stone we will never know, apparently it was erected by the local Council a few years ago, and lies alongside the Afon Bryn Saeth, at SH714407, a tributary to the Afon Cynfal.
Goronwy Pebyr has been translated as “spearman, radiant”, the first element gwr (man) and *rhonwy (an archaic name for spear). The attached epithet, Pebyr is thought to derive from the Cymric word pefr (shining, radiant). A suggested etymology for Lleu has been the shining one or radiant one based on the presence of the component 'lleu' meaning ‘light’ in Cymric. This has led to the suggestion that they may well be one and the same deity and this event was an annual duel between light and dark, remembering of course that Lleu was one of a twin; divine twins being mythemic in Proto-Indo-European in mythologies. 
The required method to kill Lleu’s has the implication of a ritual as certain conditions must be met:
Lleu cannot be killed:
a. without a spear,
b. inside a house and he cannot be killed outside,
c. he cannot be killed on horseback and he cannot be killed on foot.
How he can be killed:
a. the spear must be worked on only during Sunday at the time of Mass,
b. a bath must be prepared, this must be by a riverside, there must be a well thatched roof  over the bath; so he is neither inside or outside,
c. a buck (male) goat must be placed by the bath, Lleu must place one foot on the goat’s back and the other on the edge of the bath; so he is neither on horseback or on foot.
This triad of conditions that is required to bring about Lleu’s death immediately brings to mind the threefold death motif suffered by an individual who dies simultaneously in three ways; an acknowledged Proto-Indo-European mythological theme.
As we saw previously in the medieval verse romance Sir Gawain and the Green Knight, set in the days of King Arthur at the New Year's feast, derived originally from the much earlier 8th Century Irish tale Bricriu’s Feast, the three attempted axe cuts are symbolic of the three strikes and clearly referring to the triple death.
1. Rachel Bromwich, Three Disloyal Warbands of the Island of Britain, Trioedd Ynys Prydein (TYP): The Triads of the Island of Britain, University of Wales Press; 3rd Revised Edition, 2006.
2. "Blodeuwedd" still means "owl" in modern Welsh.
3. Will Parker, The Mabinogi of Math, 2003.
4. Bromwich, op.cit, p.65.
5. Dr G. R. Jones: The Cult of St Helen.
6. Bromwich, op.cit, p.67.
7. Michael Senior, Gods and Heroes in North Wales. Gwasg y Garreg Gwalch, Lanrwst, 1993.
8. In the study of mythology, a 'mytheme' is the essential kernel of a myth, an irreducible, unchanging element, and one that is always found shared with other, related mythemes and reassembled in various ways.
9. W J Gruffydd, Math van Mathonwy, University of Wales Press, 1928. Gruffydd suggests that what is meant here is a round, pointed thatched roof without sides.
Picture credits: These photographs, which I am assured are the Stone of Goronwy (Llech Goronwy) were emailed to me sometime ago but I have no idea of the original source.
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