History Files


European Kingdoms

Celts of Armorica




Map Domnonia (Dumnonee)

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

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 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.. The two kingdoms certainly seem to have shared a connection in their early days.

(Additional information by Edward Dawson.)

Gerenton / Gereint

Catou / Cadwy

Erbin / Urbien ap Gereint

Mistakenly named Erbin ap Custennin Corneu, of Dumnonia?

fl c.380

Guitol / Gwidol ap Gradlon

Son of the King of the Bretons.

fl c.420

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. The Riothamus of AD 469 or the son of Deroc II instead?

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.

c.500 - 520

Riwal Deroc / Ferox

Son. Nicknamed 'the Obstinate/Arrogant'.

520 - 530

Deroc / Deroch II



Deroc II may be the father of one Riotham (see above), but it is Jonas (Ionas ap Deroch) who succeeds him. The principality is now raised to a kingdom.

530 - 540

Jonas / Ionas / Wiomarch / Widimacl

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

540 - c.550

Judual / Iudwal ap Ionas

Son (born c.530). Imprisoned.

bef 550 - 560

Conomor / Cunomorus 'the Cursed'

Killed in battle against Clotair, king of the Franks.

560 - 585



585 - 607

Judual / Iudhael ap Iudwal

Son (born c.560).

607 - c.615

Haelog ap Iudhael

bef 635 - 657

JudicaŽl / St Iudicael ap Iudhael

Son? Same as Iudicael, King of the Bretons?

635 - 657

Under JudicaŽl's reign, Bro Erech is merged with Domnonia. JudicaŽl was descended on his great grandmother's side from Waroch of Bro Erech. As it seems highly probably that JudicaŽl King of Domnonia was 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.