History Files


European Kingdoms

Celts of Armorica




MapDomnonia (Domnonée)

Situated to the north east of Brittany, the earliest princes are mentioned in several Lives of the Saints. Guitol, the fourth of them, 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'.

FeatureThe 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 supply the 'Kings of the Bretons', and Domnonia itself was elevated as a result.

Domnonia (or the later form of Domnonée) 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.

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 that 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.

(Additional information by Edward Dawson and Geoffrey Tobin, and from Province and Empire: Brittany and the Carolingians, Julia M H Smith (1992), 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 Link: Encyclopaedia of Earth.)

fl 407 - 409?

Gerenton / Gereint

Possibly the second-in-command of 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). 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 Alans, 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 that are never renewed. Roman 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.

Catou / Cadwy


Erbin / Urbien ap Gereint

Son. Mistakenly named 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. He eventually returns to kill the usurper and take the throne for himself.

fl c.460


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

FeatureOne 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 Dumnonee. Even which King Deroc to claim as his father is unclear, so perhaps two separate individuals are being confused. 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.


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.

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 [that 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, 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 beach-head, it would reflect the times for him to have forged alliances with rebellious Britons, immigrant Saxons and hybrid groups who needed a seasoned battle leader.

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 predecessor, Deroc I, but it is Jonas (Ionas ap Deroch) who succeeds him and not Riotham, son of the first Deroc. 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.

bef 550 - 560

Conomor / Cunomorus 'the Cursed'

Usurper. Killed in battle against Clotair, king of the Franks.

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.