History Files

Celtic Kingdoms of the British Isles

Celts of Cymru


Dogfeilion / Dogfeiling (Romano-Britons) (Wales)

FeatureWith the expulsion of Roman officials in AD 409 (see feature link), Britain again became independent of Rome and was not re-occupied. The fragmentation which had begun to emerge towards the end of the fourth century now appears to have accelerated, with minor princes, newly declared kings, and Roman-style magistrates all vying for power and influence while also facing the threat of extinction at the hands of the various barbarian tribes which were encroaching from all sides.

FeatureIn the west, largely in what would become modern Wales, this process seems to have started earlier and taken place more quickly. Even by the start of the fifth century it is apparent that several territories had emerged here. The process seems to have been triggered by the reorganisations of Magnus Maximus in the late fourth century (see feature link), with what later tradition would claim as the creation of the 'kingdoms' of 'North Wales', 'South Wales', and 'Mid-South Wales'.

FeatureDogfeilion was a minor sub-kingdom which was located inside the eastern border of Venedotia (see feature link). It was bordered to the south by the territory of the Paganes (early Powys), to the south-west by Edeyrnion, and to the west by Rhufoniog, and formed part of early Gwynedd's overall domain. Upon the death of Cunedda Wledig, the traditional first ruler of Gwynedd, his youngest son, Dogfael, gained his inheritance and the land was named in his honour.

MapAt its height, Dogfeilion's territory seems to have extended much farther east (see the map of Cymru via the link), but this was largely lost to English incursions. The sub-kingdom's royal family, dominated in turn by Powys and Gwynedd, managed to avoid total subjugation by gaining themselves territory in the south of Britain in the form of the sub-kingdom of Glastenning, which Powys did not claim and into which Gwynedd could not easily ride.

Dogfeilion princes also controlled the sub-kingdom or territory of Pengwern to the west. As a result, they had two warbands, one across Dogfeilion and Pengwern and one in Glastenning. This gave them the resources to be major players, with family members in each area. They were able to gain a position of strength in Powysian politics (probably through marriage) and eventually became ruling princes there.

The '-ing' suffix which is sometimes seen in the Dogfeilion name is an English interpretation (or misinterpretation), showing up as 'Dogfeiling'. The equivalent Welsh suffix is '-ion' and the two seem to have been an automatic translation between the languages, with the Anglo-Saxons habitually substituted 'ing for '-ion'.

The principality and its ruling dynasty should more properly be 'Dogfeilion', although Welsh consonant shifts always leave room for uncertainty. The 'dog' in 'Dogfeil' refers to the deity Dagda (Dog/Dag 'the Good'). The '-feil' is altered '-mail' (mal) which means 'servant', and is precisely the same word as '-fael' in Cynfael (there were no regular spellings in early records which relate to this period). So 'Dogfeil' makes sense as 'servant of [the god] Dagda'.

The sub-kingdom's capital may have been at Ruthin. This name was coined for a newly-built red sandstone castle on the site called Rhuthun, from 'rhudd' and 'din', meaning 'red tower', However, it is also known as Castell Coch yng Ngwern-fôr (seemingly a more recent name), and there seems to have been a wooden tower on the hill prior to the construction of the red sandstone castle.

Prior to that a Roman-era fort was built on the hill to house a single cohort of legionnaires. This, of course, would have been modified during the subsequent Romano-British period to serve British cavalry, with a tower as a refuge. It is highly likely that this fort would have continued in use with the men of Dogfeilion, and may in part have been the wooden tower which was replaced by a red sandstone castle.

Roman Canterbury

(Information by Peter Kessler and Edward Dawson, with additional information by Mak Wilson, from The Landscape of King Arthur, Geoffrey Ashe, from Roman Britain: A New History, Guy de la Bédoyère, from History of the Kings of Britain, Geoffrey of Monmouth, from the Historia Brittonum (The History of the Britons), Nennius, and De Excidio Brittaniae et Conquestu (On the Ruin of Britain), Gildas (both J A Giles, Ed & Trans, 1841, published as part of Six Old English Chronicles (Henry G Bohn, London, 1848)), from Marwnad Cynddylan (The Lament for Cynddylan), from the Annales Cambriae, James Ingram (taken from the Harleian manuscript, the earliest surviving version, London, Everyman Press, 1912), from The Oxford History of England: Anglo-Saxon England, Sir Frank Stenton, from Wales and the Britons, 350-1064, T M Charles-Edwards (Oxford University Press, 2013), and from External Link: English Heritage.)

fl c.445

Dogfael ap Cunedag

Eighth son of Cunedda Wledig of Venedotia. First prince.

fl c.500

Elno / Elnaw ap Dogfael

Son. Gained the Dumnonian sub-kingdom of Glastenning.


Geoffrey of Monmouth's Bishop Eledenius is the little-known St Elidan, a member of the British Church who later has parish churches dedicated in his name in the Vale of Clwyd. This places him firmly within Dogfeilion territory in western Britain.

Map of Britain AD 450-600
This map of Britain concentrates on British territories and kingdoms which were established during the fourth and fifth centuries AD, as the Saxons and Angles began their settlement of the east coast (click or tap on map to view full sized)

fl c.550

Cyndrwyn Glas 'the Blue'

Son. Ruled Dogfeilion & Glastenning. Gained Pengwern.


According to William of Malmesbury, Cyndrwyn Glas settles in Glastenning with his livestock after finding it deserted, migrating there from Luit Coyt (an early connection to this place in Pengwern which will later become important to him and his offspring). His epithet, 'Glas', means 'blue', a typical Welsh naming pun for a redhead. Is this pun the origin of the name 'Glastenning' (and therefore 'Glastonbury')?

Cyndrwyn Glas appears to be a ruling prince or sub-king there, and a Cyndrwyn Fawr also appears as a leader in Pengwern around AD 613. Given the links between the Dogfeilion princes and Pengwern, this could also be Cyndrwyn Glas.

The word 'fawr' means 'great' in Brythonic/Welsh, suggesting that he has built a reputation for himself. Could he also be Cyndrwyn 'the Stubborn' of South Powys, especially given the Powysian dominance over Pengwern which provides direct link between the two?

In terms of Cyndrwyn's personal name, the first part, 'cyn', is 'dog'. This is a common naming form for Celtic leaders, appearing variously as 'cuno', or 'cune', or 'con'. The second part, 'drwyn', is yet another typically Welsh/Celtic pun which is 'trwyn' in modern Welsh, meaning 'nose, snout, nozzle, proboscis'. In other words, Cyndrwyn means 'dog nose'.

Caer Luit Coyt
The British fort at Caer Luit Coyt (Wall by Lichfield in modern Staffordshire) had been an important staging point on Watling Street, the Roman military road into North Wales, and was inherited and used as a regional capital by Romano-Britons


While Glastenning is inherited by Morfael, son of Cyndrwyn, this point marks the first appearance of the Dogfeilion in Powys and Pengwern. Morfael is also a sub-king within Pengwern, at Caer Luit Coyt, while his brother, Eiludd Powys, becomes ruler of Powys (which potentially remains overlord of the Pengwern territory).

Given Welsh emphasis on ancestry to qualify for a throne, it seems likely that a Dogfeilion leader (probably Cyndrwyn Glas) had married a daughter of the ruling prince of Powys, qualifying his descendants to rule Powys by the rules of descent of Gwynedd (which had been inherited from their ancestors, the Pictish Venicones).

Romans and Romano-Britons use primogeniture, but Pictish rules are that any descendant, regardless of the form of that descent, is qualified to inherit (meaning that even bastard sons of wayward daughters can show up and claim a piece of a territory or even a kingship). The fact that the Dogfeilion are accepted as rulers of Powys (and that part of Powys which is known as Pengwern) is very telling. There has to be a valid claim of descent.

? - c.642

Eiludd Powys ap Cyndrwyn

Son. Ruler of Dogfeilion & Powys.


In one of the bloodiest and hardest fought battles of its time, several British kings form a coalition to halt Æthelfrith of Bernicia at the Battle of Caer Legion (Chester). Cearl of the Mercians could also be involved on the British side (according to scholarly theory).

The River Dee
The River Dee probably formed the border between northern Powys and south-western Rheged during the sixth century AD, and until the fall of the latter in the early seventh century

Iago of Gwynedd and Selyf of Powys are both killed, and the battle is a disastrous British defeat. However, Æthelfrith does not occupy the territory around Chester. Just who does is unknown, and the entire history of this region from the post-Roman period to the tenth century is extremely sketchy.

One possibility is that the line of the River Dee is successfully defended by the people living just to the west of it - the Dogfeilion - who are able to claim great prestige from being the victorious defenders of the western Britons. Another possibility is that groups of Angles who are not under Bernicia's control settle the region to the east of the Dee, and are later subsumed within Mercia.

Bledric ap Custennin, king of Dumnonia, dies at the Battle of Bangor-is-Coed, which follows very soon afterwards. A certain Brochfael is named as the commander of Caer Legion at this time, and may be one of the sons of Powys' Brochfael, potentially the first ruling prince of Pengwern.

FeatureAfter this, the Dogfeilion kings appear to move in on Pengwern (perhaps due to their theoretical defence of the Dee). The monks of Bangor-is-Coed are present at the battle to pray for divine support, but they too are slaughtered. The act is seen as divine retribution for their refusal to help evangelise the English in 603 (see one of Geoffrey of Monmouth's more accurate entries about this campaign via the feature link).

The Glastonbury region seems to have experienced a power vacuum in the mid-fifth century which allowed the Dogfeilion to walk in and take over - or be appointed there, perhaps

c.642 - ?

Elaed ap Eiludd

Son. Ruler of Dogfeilion.

652 - 658

Two West Seaxe victories in 652 and 658 see them occupy the entire Glastonbury region, and the sub-kingdom of Glastenning ceases to exist, allowing the Somersaete to heavily infiltrate this region. Its overlord, Dumnonia, also suffers extensive loss of territory in the remaining parts of Somerset and in Dorset.

The fate of Morgan Glas, Elaed's cousin in Glastenning, is unknown. The Dogfeilion kings also lose Pengwern in 656, and already seem to have lost control of Pengwern's master, Powys, so now they are cut back to their ancestral territory of Dogfeilion.


Marwnad Cynddylan (The Lament for Cynddylan) laments the death of Cynddylan, ruler of Powys, at the hands of the ruling prince of Dogfeilion, marking a resurgence for the Dogfeilion side of the feud. It refers to Cynddylan and his side of the feud as 'the Cadelling', meaning that they are the descendants of Cadell Ddyrnllwg, ruler of the Paganes of the mid-fifth century.

Cynddylan is 'the battle leader', meaning (in the poet's eyes) the rightful ruler, and is given a full royal retinue of seven hundred chosen soldiers, the same number to have been defeated by Oswiu of Northumbria in his 656 defeat of Pengwern.

Flooded Somerset Levels
Even by 2013 the Somerset Levels was still prone to excessive flooding, but in the post-Roman and early medieval periods this flooding would have been a regular seasonal feature of the region

Whether Cynddylan himself really has that number of men is questionable given the fractured nature of Powysian politics at this time and the very recent catastrophic loss of Pengwern. It could instead be down to poetic largess, as a lament of this nature would clearly be written for the court of the dead prince, a court which is still resisting Dogfeilion opposition.

fl c.670

Meurig ap Elaed

Son. No known heir, so the territory could revert to Gwynedd.


This branch of Cunedda's descendants ends with Meurig, a ruling prince who is not known to have any offspring. As a consequence, Dogfeilion is very probably brought back under the direct control of Gwynedd, while the remaining Dogfeilion line fights on in Powys to achieve supremacy by around 710-730.

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