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European Kingdoms

Celts of Armorica


Domnonia / Domnonée (Armorican Romano-Britons)

The north-western corner of today's France was known during the Roman period as Armorica. The tribe of the Veneti had been the most powerful of Armorica's tribes, and that name gradually changed during the Roman occupation to Vannetais. This was how Armorica was initially known to the Britons who began migrating there in the fourth century AD, during a period in which British town life appears to have declined.

The low-key migration from Britain into Armorica seems to have picked up noticeably in the mid-fourth century, but it became a flood in the unsettled fifth century. Traditional certainly maintains that the British colony in Armorica was founded before the expedition of Constantine III in 407. People arrived mainly from the south-west of Britain, from Dumnonia and Cornubia, and each group retained its ethnic name (ergo the people in each region knew exactly what they were ethnically or tribally, regardless of who was king over them).

FeatureThis new colony of Britons formed in a region which was beginning to drift out of firm Roman control. The colony's traditional first king, Conan Meriadog, ruled Armorica as the kingdom of Vannetais, maintaining the local Gaulish tribal name. The area was permanently 'freed' of Roman control by Magnus Maximus as the first stage of his invasion of Gaul in 383 (see feature link). Conan was placed in command, with a probable capital in Vannes. The usual Celtic practice of dividing territory between sons soon created the smaller principalities out of Vannetais during the course of the fifth and sixth centuries whilst other Britons also popped over from the mainland to found their own principalities.

FeatureSituated in the north-east of Brittany, the earliest princes of Domnonia are mentioned in several Lives of the Saints. Guitol, the fourth of these princes, is named by the Life of Saint Winnoc and the Life of Saint Judicael as the son of 'Urbieni filii [son of] Catoui filii Gerentonis'. The three Armorican principalities were all subservient to the king of Brittany. Until the reign of Jonas, the rulers of Domnonia were titled princes. After that, they supplied the 'Kings of the Bretons' (see feature link), and Domnonia itself was elevated as a result.

Domnonia (or Domnonée in its later form) may have been settled by Britons of Dumnonia, probably of the royal house, while many other Britons probably entered Armorica from other parts of Britain by going through Dumnonia. According to tradition and early surviving writings, the two kingdoms certainly seem to have shared a connection in their early days. It could be conjectured that Dumnonians fled to Armorica in the face of the initial Roman conquest of Britain in the first century AD, but this seems unlikely. It had only been a century since Armorica itself was conquered and large numbers of Celts had fled in the opposite direction. They would hardly flee one Roman force now simply to hand themselves over to another. Instead, the main migration of Dumnonians seems to have taken place in the face of the post-Roman uncertainties (and sometimes chaos) of the fifth century.

Domnonia's location in relation to the other Armorican principalities also supports a settlement by Dumnonians. Four (self-identifying) sub-ethnic groups seem to have moved to Armorica to settle in a geographical order which matched that of their homelands in Britain - from west to east these were Leon, Cornouaille, Domnonia, and Rennes.

Poutrocoët was an early medieval pagus in Brittany, and the name itself is Breton in form. Contemporary accounts translate it literally into Latin, showing it as pagus trans silvam, meaning 'country beyond the forest (such as charters held by Redon Abbey). The pagus started out as part of Domnonia, and included a smaller region with the name of Porhoët. It was much larger than the other pagi, and was perhaps just 'a vast region which had escaped the primitive division into pagi' according to Karen Jankulak, after Chédeville and Guillotel). It was sparsely populated and heavily forested, so it is sometimes associated with the legendary medieval forest of Brocéliande and the inland Argoat. This would make sense, as much of inland Brittany was hilly and forested, and sparsely populated. By about AD 1000, Porhoët was a viscounty in its own right.

Roman Canterbury

(Information by Peter Kessler, with additional information by Geoffrey Tobin and Edward Dawson, from Brittany: Many Kingdoms or One?, Jean-Michel Pognat, from Province and Empire: Brittany and the Carolingians, Julia M H Smith, part of The Cambridge Studies in Medieval Life and Thought series (1992), from The Ethnology of Germany Part 3: The Migration of the Saxons, Henry H Howorth (Journal of the Anthropological Institute of Great Britain and Ireland, Vol 7, 1878), from The History of the Franks, Volume II, Gregory of Tours (O M Dalton, Trans, 1967), from The History of Normandy and of England, Francis Palgrave (1864), from La Bretagne des saints et des rois: Ve-Xe siècles, André Chédeville & Hubert Guillotel (1984), from Les anciennes structures rurales de Bretagne d'après le cartulaire de Redon: Le paysage rural et son évolution, Pierre Flatrès (Études rurales No 41, 1971), from The Medieval Cult of St Petroc, Karen Jankulak (2000), from Oral and Written: Saints, Miracles, and Relics in Brittany, c.850-1250, Julia M H Smith (Speculum, Vol 65 No 2, 1990), and from External Links: Encyclopaedia of Earth, and Rick Steve's Europe.)

fl 407 - 409?

Gerenton / Gereint

Possibly second-in-command to Constantine III.


Constantine III, usurper Western Roman emperor and ruler of Britain, sends his son, Constans, and General Gerontius to Hispania to defeat the cousins of Roman Emperor Honorius there and secure that province (Gerontius could be the Gerenton mentioned in connection with Domnonia in the Vannetais).

Dinas in Brittany
Dinan in Domnonia was a medieval residence of the duke of Brittany, a strategic port on the English Channel, and a trading centre with powerful guilds and good connections with England and Holland, so it may have been just as important to the earliest British settlers in Domnonia

Stilicho's forces in Italy rebel and he is executed. As a result of this and intrigues at the imperial court, plus the fact that Alaric's Visigothic army is roaming Etruria, Honorius is left powerless, and gladly accepts Constantine as co-emperor.


The Alani, Suevi and Vandali enter Hispania, disrupting Constantine's hold on his territory. Gerontius rebels against Constantine, and raises Maximus as his own puppet emperor. With Constantine now in serious difficulties in Gaul, further Saxon raids convince the British and Armoricans to rebel and expel Roman officials, thereby breaking ties with Rome which are never renewed.

FeatureRoman presence in Britain has been dwindling anyway, for at least the previous three decades, so the split probably produces little change, except that British officials now occupy former imperial posts. Records from this point become extremely sparse and British control on a national level appears to break down for a time (see feature link for more information).

Map of Armorica
Vannetais was created during the late fourth century AD, enjoying a peak of expansion and power up until 491 (click or tap on map to view full sized)

Catou / Cadwy


Erbin / Urbien ap Gereint

Son. Confused with Erbin ap Custennin Corneu, of Dumnonia?

fl c.430s?

Guitol / Gwidol ap Gradlon

Son of Gradlon, king of the Bretons.

fl c.440

Deroc / Deroch (I)


fl c.450?


Usurper and former general.

Upon the death of Deroc, his son is exiled to Britain when Deroc's former general, Marchell, seizes control of the principality. Riotham eventually returns to kill the usurper and take the throne for himself, but his precise identity is open to a great deal of question.

fl c.460


Son of Deroc (the Riothamus of AD 469?).

FeatureA certain Riothamus is remembered as one of the greatest leaders of Britons in the mid-fifth century, but it is unclear whether he is a leader of insular Britons, and possibly even high king of Britain or, less magnificently, Riotham, the princely son of Deroc of Domnonée. Even which King Deroc to claim as his father is unclear, so perhaps two separate individuals are being confused (see feature link for more).

He could be Riothamus, leader of a 12,000-strong British expedition against the Visigoths in Gaul, in alliance with Soissons, Burgundians and the Western Roman empire. He could be Ambrosius Aurelius of Britain and therefore linked with the refortification of Cadbury Castle. Or he could be a more minor Breton prince.

Cadbury Castle
Even today, Cadbury Castle presents the image of a powerful and defensible location, with views across the whole of Somerset giving it a level of strategic importance


FeatureAccording to tradition Cerdic and his (young) son Cynric, together with Saxon and possibly some Jutish companions, land in five ships on the south coast of Britain at Cerdices ora, and begin a takeover of the local Jutish, Saxon and sub- Roman territories. The Jutes and Saxons who are already settled there are apparently already referring to themselves as the West Seaxe 9see feature link for more on this general subject).

Geoffrey Tobin suggests that this 'landing' of 495 be taken literally. The Encyclopaedia of Earth states 'Tidal streams in the eastern English Channel and [around the] Channel Islands area [are] generally anti-clockwise, whilst the western entrance of the Channel has a clockwise tidal circulation [which is] wedded to the Celtic Sea'.

Visualising this, one can expect frequent landings in Hampshire from both Brittany and Flanders by skirting the English coast, and return journeys to the Cotentin peninsula then passing along the coasts of Brittany and France. Cerdic may take one of these routes while the Saxons take the other.

If the strong states of Domnonia and Dumnonia are one kingdom in the fifth century, and Cerdic is an ambitious noble, perhaps a fractious younger brother of the magistrate or ruler of this region, then this would explain his actions in landing near Southampton (as Bretons later often did) and taking on the loyalist Natanleod (in 508). Having established a beachhead, it would reflect the times for him to forge alliances with rebellious Britons, immigrant Saxons, and hybrid groups who need a seasoned battle leader.

Portchester Castle
The Roman walls of Portchester Castle (British Caer Peris) would still have been standing when this former Saxon Shore fort was captured by a Saxon chieftain in AD 501, possibly ending the independence of the territory of Rhegin (click or tap on image to read more about this castle)

fl c.500 - 520

Riwal Deroc / Ferox

Son. Nicknamed 'the Obstinate/Arrogant'.

fl 520 - 530

Deroc / Deroch (II)



Deroc II may sometimes be confused with his namesake predecessor, Deroc (see above), but it is Jonas (Ionas ap Deroch) who succeeds him and not Riotham, son of the first Deroc (sometimes stated as being the case, but perhaps based upon a chronology which differs from the one being used here). The principality is now raised to a kingdom.

fl 530 - 540

Jonas / Ionas / Wiomarch / Widimacl

Son. Killed by Conomor. m dau of Budig II, king of the Bretons.

fl 540 - c.550

Judual / Iudwal ap Ionas

Son. Born c.530. Imprisoned by Conomor.


Judual is imprisoned by Conomor of Poher so that the latter can seize his kingdom. Conomor's name means 'great dog'. In the Life of St Pol de Leon (St Paul Aurelian) completed in 883, there is a 'King Marc whose other name is Quonomorus' - or Cunomorus - meaning 'hound of the sea'.

This may be a confusion between this Conomor, prince of Poher and king of Domnonia and the Cyn-March ap Meirchion of Cornubia, or even the Marcus Conomari of Dumnonia who had ruled in the early fifth century. It is hard to be sure if both Cyn-March and Conomor hold any power in Poher, or if the former is merely present due to the aforementioned confusion.

Celtic rock inscription
The migrating Britons would have entered a landscape which was littered with the relics of their continental Celtic cousins, including this rock inscription within Poher's territory

bef 550 - 560

Conomor / Cunomorus 'the Cursed'

Prince of Poher. Usurper. Killed in battle.


Conomor is said to have emigrated from Britain into the Vannetais in the first half of the sixth century, and then to have build a castle at Carhaix in Poher. Breton tradition presents Conomor as a local 'bluebeard' who does not spare the life of his last wife. When threatened by his rival Breton warlords and abbots, he seeks help from Childebert, king of the Franks of Paris, but is killed around 560 in a battle against Chlotar, Childebert's more powerful superior.

fl 560 - 585

Judual / Iudwal ap Ionas


585 - 607

Judual / Iudhael ap Iudwal

Son. Born c.560.

607 - c.615

Haeloc / Hoel / Haelog ap Iudhael

Son. Hoel III of the Bretons?

bef 635 - 657

Judicaël / St Iudicael ap Iudhael

Brother. Same as Iudicael, king of the Bretons?

635 - 657

Under Judicaël's reign, Bro Erech seems likely to be united with Domnonia. Judicaël is descended on his great grandmother's side from Waroch of Bro Erech. As it seems highly probably that Judicaël, king of Domnonia, is also Iudicael, king of the Bretons, Domnonia's kings probably continue as high kings of Brittany, and Domnonia effectively becomes the chief state of the colony, their kings listed as kings of the Bretons.

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