Tuesday, December 5, 2017

CATO/CADWY AT DINDRAITHOU: A FINAL IDENTIFICATION FOR ARTHUR'S FORTRESS


Plan of Camelot Castle, Somerset

Cadbury Camp, North Somerset

In a previous blog entry (http://mistshadows.blogspot.com/2017/12/note-on-draydon-fort-in-somerset-better.html), I set forth the arguments for Arthur's Dindraithou as a fort at various sites in Somerset and Cornwall.  These tentative identifications relied upon -draithou being interpreted either as a Welsh attempt at an English element or as a rendering of a Cornish place-name.

Here I wish to once again emphasize the significance of the odd co-rulership of Arthur and Cado (Cato, Cadwy) at Dindraithou.

The important question here, of course, is why the author of the Life of St. Carannog felt it necessary to have Arthur share rule of this particular fort with the Dumnonian king Cadwy. Obviously, this could simply be a convenient chronological fix.  Cadwy was born (according to P.C. Bartram's rough estimate) in c. 500 A.D.  But I find that hagiography, like folklore and myth, does not usually bother itself too much with adhering to accuracy in such matters.  In addition, as Arthur is indisputably the most famous figure, why risk diminishing his power and reputation by forcing him into a peculiar dual-kingship role with Cadwy?

I cannot help but see in Cadwy's presence at Dindraithou an attempt to indicate that we are dealing with one of the Cadbury forts.  In other words, Dindraithou is a Cadbury fort.  As it was presumably called after Cadwy, yet Arthur was there (in whatever capacity), the only way to reconcile this apparent contradiction was to make both chieftains ruler of the place.  The author of the Vita, in other words, knew that Dindraithou was a designation for a Cadbury fort.

If this is so, we must fall back on Dindraithou as either 1) a 'fort of the traethau' or "fort of the shores" or 2) a Welsh rendering of the Irish Dinn Tradui/Tredui, 'triple fossed fort.'   I will consider a third possibility below.

If Dindraithou is No. 1, then only the Cadbury Camp fort in North Somerset works.  As I've mentioned before, with the change in sea level at Arthur's time, Cadbury Camp atop its ridge overlooked the often flooded Somerset Levels.  Where the ridge met the water could have been called "the traeths" - although the word traeth itself is reserved for a shore associated with an estuary.  Cadbury Castle was too far east and was not close enough to the flooded area of the Somerset Levels.  

If No. 2, either of these two forts are candidates, as both are multivallate.  

So how do we decide between the Cadburys?

Archaeology may have done that for us, fortunately.  The famous excavations of Leslie Alcock showed conclusively that Cadbury Castle underwent a massive rebuild at Arthur's time. Because of the River Cam and Camel villages here, local tradition had long identified the place with Camelot. [Camel comes from Cantmael and has nothing whatsoever to do with Camelot, a late French attempt at rendering Campus Elleti in Wales.]

However... and this is a big 'however', if I'm right and Illtud is Arthur's father, I would opt for Cadbury Camp.  Why?  Because the Llydaw/Letavia/'Brittany' of Illtud's father, Bicanus, is almost certainly the Leadon Valley area of what was Dobunni territory.  Dobunni territory extended to Cadbury Camp in North Somerset, and Cadbury Camp is pretty much directly across the Mouth of the Severn from the Dinas Powys where Illtud served as military commander.

Another smaller Cadbury fort is to be found at Cadbury Hill 



Alas, there is no archaeological evidence for early medieval reuse of either of these two hillforts.

DINDRAITHOU (CAIR DRAITOU?) AND THE DUROTRIGES

It has occurred to me that if Cadbury Castle in Somerset is Dindraithou, that there might be one more possible explanation for the latter name.  This idea is a stretch, but perhaps worth mentioning.  

Ilchester just a little ESE of Cadbury Castle (see map below) appears to have belonged to the ancient Durotriges tribe. Here is the entire entry for the Durotriges from Rivet and Smith's THE PLACE-NAMES OF ROMAN BRITAIN:

- Ptolémée, II,3,13 : Dourotriges ( = DUROTRIGES);

- Inscriptions RIB 1672 (pierre provenant de Cawfields sur le Mur d'Hadrien) : C(IVITAS) DUR(O)TR(I)G(UM) (L)ENDIN(I)ESIS.

- Inscription RIB 1673 (pierre provenant de près  de Housesteads sur le Mur d'Hadrien) : CI(VITAS) DUROTRAG(UM) LENDINIESI(S).

(Both stones are probably of A.D. 369. For the spelling of the adjectival form of the civitas-name, see LINDINIS) 

It is by no means certain that the name bas -i-. though it is traditionally cited in this form. While this is present in all the Ptolemy MSS, it could be an error going back to the archetype or to Marinus. RIB 1672 omits the vowel, but RIB 1673 plainly writes -a- (A) and it is not likely a member of the civitas literate enough to be given the task of cutting the iscription would mistake the spelling of the name of his own people. For a similar (reverse) error in Ptolemy, compare VINDOGARA, which has Ouando- (= Vando-) in all the MSS at II, 3, 7.

DERIVATION. This name is obscure. It be divided Duro-triges or Durot-riges. It is tempting to think it another of the many names in *duro- 'fort ', although Britain we know this element chiefly applied to early Roman forts on low ground, so that it could hardly apply particularly in the name of a tribe whose region contains many spectacular hill-forts (which would have had *-dunon names). However, this *duro- does enter into a few names such as the two British Durocornovium and in Gaul ethnie Durocasses. Holder suggested (I. 1387) that the name might be a reduction of older *Durot(o)-riges, that is *duro- ' fort ' with some kind of suffix or infîx when in composition; but then there is no parallel for this among all the very numerous Dura- names.

The second element is possibly -riges, a plural of *rig- ' king ' which appears in several ethnic names, such as Gaulish Bituriges 'kings of the world'. Watson CPNS 16, note, identifies an element -raige (for older -rige ?) in Irish ethnic names, e.g. Dartraige (dart 'year-old bull or heifer') > Dartry, Cattraige (catt 'wild cat'), Luchraige (luch 'mouse'), and even though these seem somewhat unheroic names, they may have had totemic significance and are acceptable enough; but we have no evidence that in the present name *durot- is an animal-name which would fit into this series. If the second element is an unknown -triges, the British name might be paralleled by the Allotriges (= Allotriges : Strabo III, 4, 7 ; in Ptolemy II, 6, 7 they are the Autrigones  (= Autrigones), of Hispania Tarraconensis, with Allo- probably as in Allobroges of Gaul.

If -a- is right, the etymological possibilities are less good. A -rag- element is unknown, but -trag- is said by Dottin LG 193 to be a 'terme de composé' and is related by him to Irish traig 'foot' and Welsh traed (pi.). But this does not relate well semantically to a first element *duro-. The name must be left unresolved.

IDENTIFICATION. A people of southern Britain with their capital at Durnovaria, Dorchester; for the probability that their civitas was at some time subdivided, with a second capital at Ilchester, see Lindinis. Ptolemy attributes to them only Dunum (= Dunium, Hod Hill?), but the distribution of their pre-Roman coins indicates that they occupied Dorset, parts of Wiltshire, Hampshire and somerset, and perhaps the extreme eastern part of Devon.

Proximity of Cadbury Castle to Ilchester/Lindinis of the Durotriges

I can think of a very good word which might be brought into the context of -triges or -trages:

abode Proto-Celtic *trīko-, SEMANTIC CLASS: technology, cf. Old Welsh tricet ‘resides’, Welsh trig ‘stay, a residing, abode, dwelling(-place)’, Breton (milin) tric (Old Breton) ‘gl. permanendi in stupris ‘staying sullied’

From the GPC:

trig1 
[bôn y f. trigaf1, trigiaf: trig(i)o; cf. H. Lyd. (milin) tric, gl. permanendi in stupris; ansicr yw union ystyr rhai o’r enghrau. isod] 
eg. ?a hefyd gyda grym ansoddeiriol.
Arhosiad, preswyliad, preswylfa, trigfan:
stay, a residing, abode, dwelling(-place). 

If this is -triges, then we have simply "Fort-dwellers", a very acceptable name for a tribe known for its many fine forts.  We may compare this name to that of the nearby Atrebates, whose name means simply "settlers, inhabitants" (Rivet and Smith; *ad-, to, + *treba, to inhabit). 

Again citing Rivet and Smith, "...*duro- 'fort, walled town', apparently usually on low ground (and named in contrast to *duno- 'hill-fort')...".  Given the spelling -trag-, and knowing as we do that /t/ (and from t, d) can substitute for /c/, could we suggest that -draithou (or the Irish tredui/tradui) is a corruption of trig/trag and that Din-/Duno- has been substituted for Duro-?  In other words, at some point, by some process, Duro-triges/trages became Duno-triges/trages?  And that it is this last we happen to have preserved in the form Dindraithou?

Even if this doesn't work linguistically, it is evident that Cadbury Castle was, at one time, in the tribal kingdom of the Durotriges.  




Saturday, December 2, 2017

NOTE ON THE DRAYDON, DUNDRY AND TRETHEVY FORTS IN SOMERSET AND CORNWALL; A BETTER CANDIDATE FOR DINDRAETHOU?

If we do go with something like Welsh traethau for the Dindraethou fort name, there are a couple other options - although it takes Cadwy and Cadbury Castle out of the picture. [I myself tend to give precedence here to the Welsh source, rather than to the Irish for Dinn Tradui.]

DRAYDON

Not far south of Carhampton and Williton (places mentioned in the Life of St. Carannog) there is a hillfort called Mounsey Castle.  It is hard by a place called Draydon.  According to Ekwall and subsequent place-name specialists, Draydon is to be derived from

OE draeg  a place where something can or has to be dragged (boats, timber); derived from draga to draw

+ dun

When I looked up traeth in the Geiriadur Prifysgol Cymru, I noticed that the word may be related to Latin tractus:

traeth1
[H. Grn. trait, gl. harena, Crn. Diw. treath, H. Lyd. cundraid, gl. lidona, Llyd. C. traez, Llyd. Diw. traezh, H. Wydd. tracht: ?bnth. Llad. tractus ‘tiriogaeth, bro’]
eg. ll. -au, -oedd, treythydd, ?traith.
Ardal eang o dywod neu gerrig mân ar lan môr, glan y môr, tywyn, arfordir; moryd, aber; ?bro, ardal; hefyd yn ffig.:
beach, (sea)shore, strand, coast; estuary

The Lewis and Short Latin Dictionary at Perseus gives the following meanings to tractus:

a drawing, dragging, hauling, pulling, drawing out, trailing

Thus, is is quite possible that Dindraethou is a Welsh attempt at Draydon and Arthur and Cadwy's fort in this instance is Mounsey Castle.  Here are the Pastscape listings for this fort and the adjacent Brewer's Castle:

http://www.pastscape.org.uk/hob.aspx?hob_id=35638

http://www.pastscape.org.uk/hob.aspx?hob_id=35635

Could it be that Cadwy and Arthur are said to rule from here precisely because these are, essentially, "twin forts", divided from each other only by the River Barle?  In other words, Cadwy held one and Arthur the other?



DUNDRY

Of the same etymology as Draydon, but with the place-name elements arranged to match that of Dindraithou, is Dundry in Somerset.  The great Maes Knoll hillfort is located at the eastern end of Dundry Down ridge.  




Maes Knoll is a very large fort - much more impressive than Mounsey Castle.  My own personal feeling is that if Dindraithou were an impressive site - and one associated rightly or wrongly with the famous Arthur - then Dundry must be the place.  

Maes Knoll is typically considered to be one of the chief forts of the Dobunni tribe.  Interestingly, the Leadon Valley region, which is where I put the 'Letavia/Llydaw' of St. Illtud's father, Bicanus, was in territory once controlled by the Dobunni.  I will have more on Arthur and the Dobunni in a future blog piece.

TRETHEVY (TREDHEWI) NEAR TINTAGEL

'Dewi's farm' near Tintagel, called Tredwy in Hollinshead's CHRONICLE, could also be linked to 'draithou.' There are a number of other such places in Cornwall, including Trethevey near the Killibury Castle fort (Arthur's Kelliwic).  This last, however, is apparently from an earlier Tiwardewi and is thus not a very good candidate.  

Needless to say, these sites do not work for an Arthur close to Carhampton and Williton.  

There is absolutely no possibility, as is often cited, that Dunster = Dindraethou.  The early forms (spellings) of Dunster and its proposed etymology do not allow for this identification.  Bat's Castle hillfort near Dunster cannot, therefore, be Dindraethou.  

YET ANOTHER REASON WHY ARTHUR WAS SAID TO HAVE BEEN BORN AT TINTAGEL?

Church of St. Materiana, Tintagel

Many scholars (myself included) have provided explanations for why Geoffrey of Monmouth chose Tintagel as Arthur's birthplace.  Now, as I result of my work on Uther at Dinas Powis near the Ely River, I may have another reason.

According to the 'Pa Gur', Mabon son of Modron was Uther's servant in Ely.  Illtud, whom I've just identified with Uther, brought his wife to the court of Pawl Penychen.  It is my belief this court was the Dinas Powis fort.

At Tintagel, the earliest known church is that of St. Materiana, the 'Holy Mother.'  While this saint's name is subject to various alternate spellings, she has been most strongly linked to Madrun/Madryn, or Matrona, the divine mother of Mabon.

In my book THE MYSTERIES OF AVALON, I proposed that the Tintagel promontory was, in fact, the Roman period Herakleous Akron or Promontory of Herakles. The name Eigr would appear to be a reflection of Hera Akraia as the mother of Herakles and/or a designation for the promontory itself.  Arthur's conception story matches not only that of the Irish Mongan, but of Herakles himself.  The idea, then, is that Arthur, metaphorically speaking, is a Hercules and his mother is a goddess - or, one might say, a divine mother, i.e. Modron.

The actual birthplace of Arthur would, undoubtedly, have been Dinas Powis in Glamorgan.  


Friday, December 1, 2017

Dindraithou and Cadbury Castle in Somerset

Cadbury Castle, Somerset

In the past, I had opted for a Welsh interpretation of Dindraithou (VITA of St. Carranog) or 'Cair Draitou' (HISTORIA BRITTONUM) as "Fort of the Shores".  This meant that I was forced to look for a Cadbury fort (Arthur and Cadwy are ruling Dindraithou in the VITA) on the "shores", given that Welsh traethau meant exactly that.  I went to sources such as Rivet and Smith's AN ATLAS OF ROMAN BRITAIN (p. 13) and more recent studies such as -


- so that I might show that the only Cadbury or Cadwy's burg/fort that might be on the 'shores' of the sea would be Cadbury Camp in North Somerset. Alas, archaeology did not support my identification, for there is no evidence of sub-Roman habitation of Cadbury Camp.

Thus, I have been forced back upon the Irish version of the name, i.e. Dinn Tradui, the 'triple-fossed fort.'  This description, combined with the presence of Cadwy, fits only the great Cadbury Castle at South Cadbury, Somerset.  It has long been recognized through archaeological work that this site was occupied during the Arthurian period.

I must now confess to believing that Arthur, son of Illtud, the terrible warrior, served the Dumnonian king Cadwy at this fort in much the same way as Illtud had served his master Pawl Penychen at Dinas Powis.  

In the near future I will again address the Arthurian battles, this time assuming for the sake of argument that Arthur son of Illtud was serving as the military commander based at Cadbury Castle.

NOTE ON THE DRAYDON AND DUNDRY FORTS IN SOMERSET

If we do go with something like Welsh traethau for the Dindraethou fort name, there are a couple other options - although it takes Cadwy and Cadbury Castle out of the picture. [I myself tend to give precedence here to the Welsh source, rather than to the Irish for Dinn Tradui.]

DRAYDON

Not far south of Carhampton and Williton (places mentioned in the Life of St. Carannog) there is a hillfort called Mounsey Castle.  It is hard by a place called Draydon.  According to Ekwall and subsequent place-name specialists, Draydon is to be derived from

OE draeg  a place where something can or has to be dragged (boats, timber); derived from draga to draw

+ dun

When I looked up traeth in the Geiriadur Prifysgol Cymru, I noticed that the word may be related to Latin tractus:

traeth1
[H. Grn. trait, gl. harena, Crn. Diw. treath, H. Lyd. cundraid, gl. lidona, Llyd. C. traez, Llyd. Diw. traezh, H. Wydd. tracht: ?bnth. Llad. tractus ‘tiriogaeth, bro’]
eg. ll. -au, -oedd, treythydd, ?traith.
Ardal eang o dywod neu gerrig mân ar lan môr, glan y môr, tywyn, arfordir; moryd, aber; ?bro, ardal; hefyd yn ffig.:
beach, (sea)shore, strand, coast; estuary

The Lewis and Short Latin Dictionary at Perseus gives the following meanings to tractus:

a drawing, dragging, hauling, pulling, drawing out, trailing

Thus, is is quite possible that Dindraethou is a Welsh attempt at Draydon and Arthur and Cadwy's fort in this instance is Mounsey Castle.  Here are the Pastscape listings for this fort and the adjacent Brewer's Castle:

http://www.pastscape.org.uk/hob.aspx?hob_id=35638

http://www.pastscape.org.uk/hob.aspx?hob_id=35635

Could it be that Cadwy and Arthur are said to rule from here precisely because these are, essentially, "twin forts", divided from each other only by the River Barle?  In other words, Cadwy held one and Arthur the other?



DUNDRY

Of the same etymology as Draydon, but with the place-name elements arranged to match that of Dindraithou, is Dundry in Somerset.  The great Maes Knoll hillfort is located at the eastern end of Dundry Down ridge.  




Maes Knoll is a very large fort - much more impressive than Mounsey Castle.  My own personal feeling is that if Dindraithou were an impressive site - and one associated rightly or wrongly with the famous Arthur - then Dundry must be the place.  

There is absolutely no possibility, as is often cited, that Dunster = Dindraethou.  The early forms (spellings) of Dunster and its proposed etymology do not allow for this identification.  Bat's Castle hillfort near Dunster cannot, therefore, be Dindraethou.  

COMING SOON: A New Look at Arthur and Cadwy's Dindraithou

Cadbury Castle, Somerset

UTHER PENDRAGON DISCOVERED AT LAST!

Church of St Illtyd, Llantwit Major, Vale of Glamorgan

In the notes to this posted map -

http://mistshadows.blogspot.com/2017/11/dinas-powis-and-arthurian-sites-in.html

- I indicated that Illtud the soldier, b. c. 470 A.D. (eventually to become the famous St. Illtud), visited the court of Pawl Penychen and ended up becoming that chieftains' military commander.  I hinted at the strong possibility that Pawl's fort was Dinas Powis in Penychen, as this stronghold has proven early Dark Age occupation.

Earlier, I had made a case for Uther Pendragon belonging to this same fort, as it is very close to the Ely River and Uther's servant Mabon is placed on or near the Ely:

http://mistshadows.blogspot.com/2017/11/pa-gur-yv-y-porthaur-and-ruling-center.html

What I did not know, until I looked into St. Illtud in more detail, was that he was referred to as 'farchog', "knight", and filwr, 'soldier/warrior', as well as  'princeps militie' (militum princeps) and magister militum (https://freidok.uni-freiburg.de/dnb/download/6837).  But, even better, at the end of his VITA we are told of a 'terrible soldier/warrior', which though of a heavenly nature and left unnamed, is plainly the returning spirit of the old soldier Illtud, out to retrieve his stolen bell:

From the Life of St. Illtud:

In meridiana autem hora, dum rex quiesceret in tentorio campestri in planicie affixo, diuidereturque
maxima predatio, uisum est regi quod quidam terribilis miles suum pectus lancea perforasset, atque
post perforationem nemini uisum. [...] Timoratus imperauit sacrilego exercitui reddere Deo et
sanctissimo Iltuto totam predationem, promittens deinceps emendationem, atque in honore eiusdem
sancti edificauit templum, et seruentibus in templo concessit in quo stetit territorium. Hec emendatio
tamen profuit suo spiritui, recessit enim ab hoc seculo .ix.no die propter nequitie uindictam.

At the hour of noon, while the king rested in a field-tent put up on a plain, and the immense booty was being divided, it seemed to the king that some terrible soldier had pierced his breast with a spear, and after the piercing he was seen of none. […] Full of dread he bade his sacrilegious army to restore to God and to the most holy Illtud all the plunder, promising thereafter amendment, and in honour of the same saint he built a church, and to those serving in the church he granted territory in which it stood. This amendment, however, profited his spirit, for he departed from this life on the ninth day as punishment for his wickedness (VI, §25).

We may thus place Illtud as the terrible warrior at Dinas Powis - the same place Uther [Pen]dragon, the Terrible [Chief-]warrior, is placed in the 'Pa Gur.'

[NOTE: Uther Pendragon appears to originally have been called simply Uther Dragon. We know this is so by looking more closely at the guide-title of the ‘Uther Pen’ poem.  After receiving false or conflicting or just plain confusing information on this from several sources, I finally asked Dr. Maredudd ap Huw, Manuscripts Librarian, Department of Collection Services at the National Library of Wales.

Dr. Huw’s response, in full:

“Firstly, I confirm that there is no ellipsis indicated in the manuscript, and that the gloss (or more correctly guide-title) reads 'mar. vthyr dragon.'

Secondly, on looking at the manuscript, it appears that the guide-title is written by the main scribe to inform the rubricator, who subsequently added the abbreviated title. The red ink of ‘n’ in ‘pen’ appears to cover the letter ‘d’ of ‘dragon’.

I regret that I am not in a position to speculate as to why the rubricator did not follow the exact wording offered by the scribe in the guide-title.”

This last is an important observation. The rubricator (called such because he used red ink) wrote ‘marvnat vthyr pen.’ for the main scribe’s ‘mar. vthyr dragon.’]

But how can Illtud be Arthur's father?  The Welsh sources insist he was Arthur's cousin.  Their mother's were said to be sisters, both daughters of Anblaud Wledig of Ercing.  Illtud's father was Bicanus of Letavia/Llydaw, not here Brittany, but instead a designation for the Leadon Valley (https://mistshadows.blogspot.com/2018/10/how-welsh-tradition-confirms-that.html), between the Wye and the Severn, bordering on Ercing.  According to the ever-unreliable Geoffrey of Monmouth, Uther came to Ercing from Brittany.   Illtud's wife Trynihid is also said to have been from Brittany.

I think the problem can be dumped squarely in the lap of Geoffrey of Monmouth.  In my book THE MYSTERIES OF AVALON, I demonstrated that Ygerna, Welsh Eigr, is simply a word used for the Tintagel promontory, or perhaps a goddess title associate with that promontory.  She most certainly was not Arthur's mother, and Geoffrey's motivations for selecting Tintagel as Arthur's birthplace were largely political.  But once she had been introduced into Arthur's story, a problem was created: Illtud the terribilis miles became Uther Dragon.  And, at some point, it was forgotten that Uther was Illtud.  With no known parentage for Eigr, she was made yet another of the many children of Anblaud of Ercing.  And this meant, in turn, that Illtud was of the wrong generation to have been Arthur's father.  He became Arthur's cousin instead.

Illtud is probably the Eldadus, Bishop of Gloucester in Geoffrey of Monmouth.  I say this because Illtud at Dinas Powys was in Glywysing, and Glywys is an eponym invented for Caer Gloyw/Glevum/Gloucester.

Chapter 2 of the VITA SANCTI ILTUTI calls the living Illtud "miles magnificus."  We may compare this again with Uther [Pen]dragon:

W. uthr

fearful, dreadful, awful, terrible, tremendous, mighty, overbearing, cruel; wonderful, wondrous, astonishing, excellent. 

L. magnific.us                 

splendid/excellent/sumptuous/magnificent/stately; noble/eminent; proud/boastful

A NOTE ON GWYNLLYW, BROTHER OF PAWL PENYCHEN

Pawl Penychen's brother Gwynllyw, who features largely in the Life of St. Cadog in connection with Arthur, was also described as terrible in a military sense.  From the Life of St. Gwynllyw:

Deinde regressi sunt onerati ad naues [...] Dum hinc inciperent uela erigere [...] uidebant unum
terribilem equitante die et nocte, et persequentem illos ex omni parte. Eques iste terribilis sanctus
erat Gunlyu, qui celitus missus fuerat, ut obsisteret sacrilegis.

Then they returned to their ships burdened […] When from this place they began to hoist sails […]
they saw a single being, one terrible, riding day and night, and pursuing them on every side. That
terrible rider was holy Gwynllyw, who had been sent from heaven to withstand the sacrilegious ones
(VGu §12).

However, Gwynllyw's territory lay east of the Taff, while that of Pawl extended west of that river.  Gwynllyw, therefore, did not rule from Dinas Powis.




No 'Cornwall' at Coedcernyw, Gwynllwg (modern Monmouthshire)

The "Cornwall'" or Cernyw/Kernyw thought by many to be present at Coedcernyw in Monmouthshire is not, as it turns out, a cernyw name at all.

It is instead merely Coed + carnou, the plural for the word carn, "cairn, barrow, tumulus, mound, rock; heap, pile."

We have evidence for this in early forms for the place-name:

https://historicplacenames.rcahmw.gov.uk/placenames/headname/44200347-a60f-4f92-bf31-d43405564a35

Plus, the geography fits Coed-carnou, while there is no 'horn' or anything else which would merit the cernyw name. 

Not only are Great Pen-carn and Middle Pen Carn  and Pen Carn nearby in the parish, but also in the parish is a great stone chambered tomb:

http://www.coflein.gov.uk/en/site/307811/details/gwern-y-cleppa-long-barrow

We can dispense with the notion, therefore, that this supposed Welsh "Cornwall" had anything whatsoever to do with Arthur.