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Celtic Kingdoms of the British Isles

Celts of Cymru


Rhos / Lleyn (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'.

Apparently originally a Roman district which later became a Welsh cantref, it was granted to, or was acquired by, Venedotia during the creation of this principality by Cunedda (sometimes shown in later Welsh texts as Cunedag). It was handed down to one of Cunedda's grandsons, probably in the mid or late fifth century AD, an event which saw it converted into a sub-kingdom of what was becoming better known as Gwynedd.

A short period of personal expansion of territory was enjoyed by the ruling princes of Rhos within Gwynedd's overall borders, during which they gained Afflogion on the other side of Gwynedd. Then the sub-kingdom was apparently drawn back under the direct control of its Gwyneddian overlord.

The origin of the name is obscure. It may have its basis in the name of the former Roman district, but perhaps more likely is the fact that the word 'rhos' means 'moor, heath' in Welsh. The third choice is that it was a personal name (Ross in Scotland is the northern equivalent), although a factor against this is the lack of any Ross who is connected with the kingdom.

FeatureThe principality was ruled from a capital at Din Arth, in the north-western coastal corner of the territory, overlooking Liverpool Bay. The name Din Arth means 'tower of the bear', literally 'Bear Tower', something which has been used to link one or other of Rhos' first two kings to Arthur Pendragon. The word 'din' is a variant of 'dun', applied only to towers after the original meaning of 'dun' was reassigned to the Latin castra in the mangled word 'caer' (see Caer Gloui, for example). The sub-kingdoms of Gwynedd are explored in more detail in the accompanying feature (see link, right).

The territory is sometimes also known as the principality or territory of Penllyn, probably only for one reason - a curiosity which seems to date to a point shortly before the Gwyneddian takeover of the region. A certain Cunoricus (Cynyr Ceinfarfog in later Welsh sources) is claimed as governing the cantref of Pebidiog within the kingdom of Dyfed in the late fifth century.

Caer-Gynyr (later known as Caer Cai) near Bala in Penllyn is also claimed as being his - which raises the possibility of an interesting scenario. It seems unlikely that the first Gwyneddian ruler of Rhos was in place before about AD 480, which raises the prospect of Cunoricus being a Romano-British warlord or official who was replaced or succeeded by the newcomers who now ruled Gwynedd. Such an outcome would certainly have been a sign of the times on Britain's western coastline.

Roman Canterbury

(Information by Peter Kessler, with additional information by Edward Dawson, from Ancestry of the Kings and Princes of Wales (genealogical document in Old Welsh), from The Lives of the British Saints: the Saints of Wales and Cornwall and such Irish Saints as have dedications in Britain, Volume II, S Baring-Gould (1907), from De Excidio Brittaniae et Conquestu (On the Ruin of Britain), Gildas (see feature link at AD 517) (J A Giles, Ed & Trans, 1841, published as part of Six Old English Chronicles (Henry G Bohn, London, 1848)), from Wales and the Britons, 350-1064, T M Charles-Edwards (Oxford University Press, 2013), from Welsh Genealogies AD 300-1400, Peter Bartrum, from the Historia Brittonum (The History of the Britons), Nennius, from the Annales Cambriae, James Ingram (taken from the Harleian manuscript, the earliest surviving version, London, Everyman Press, 1912), from A History of the English Church and People, The Venerable Bede (Leo Sherley-Price translation - revised by R E Latham), and from External Links: Mysterious Britain & Ireland, and Ancient Wales Studies.)

fl c.480 - 517

Owain Ddantgwyn 'White-Tooth'

Youngest son of Einion Yrth of Venedotia. Murdered.


FeatureOwain is murdered by Maglocunus (Maelgwyn Gwynedd) almost as soon as the latter acquires the throne of Venedotia. As Owain rules during the last decades of the fifth century, he is sometimes equated with Arthur Pendragon (see feature link).

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)

He is also sometimes claimed as a ruling prince of Gwynedd itself (and therefore over-king of Gwynedd's many sub-kingdoms of this time which include Rhos). The thin source material shows his brother, Cadwallon Lawhir, as over-king of Gwynedd in the very same period.

517 - c.540

Cynlas Goch 'the Red' ap Owain

Son. Cinglas / Cuneglasus. Mentioned by Gildas.


The sense of humour sometimes exhibited by the Welsh (even today) in naming their offspring is evident in Cynlas Goch. Perhaps better known as Cuneglasus, Cunoglassus, or Cinglas in his own time, he is mentioned in records as being ruddy (a redhead), but his name literally means 'blue dog' ('cuno-' meaning 'dog' and 'glasus' meaning 'blue').

FeatureDenounced by the monk, Gildas, in the mid-fifth century as one of the 'five tyrants' (see feature link), Cynlas may be responsible for moving the capital to Dinerth. This is a hill fort on Bryn Euryn in Llandrillo-yn-Rhos.

Even today the road which runs below the hill's western side is called Dinerth Road, while Dinarth Hall is close by. Archaeological excavations here have revealed a massive stone wall of the correct period which may be three metres high when in use.

Medieval monasticism
Apart from a few examples, Latin monasticism was torpid by AD 500, and had inspired only a few pioneers in the British Isles when Gildas wrote - but within ten years of his writing, monasticism had become a mass movement

fl c.540

St Einion Frenin 'the King' / Enniaun

Brother. Allowed to absorb Afflogion into Rhos. 'King of Lleyn'.

fl c.540

St Seiriol

Brother. Born c.494.

fl c.540

St Meirion



At some point in his lifetime, Einion inherits the minor territory of Afflogion on the Lleyn peninsula after the death of its last appointed ruler. That last ruler may be Afloyg ap Cunedda, a son of Cunedda Wledig, founder of the Venedotian principality, although it is more likely to be an unknown grandson. Einion Frenin, or St Einion, now holds both eastern Gwynedd and the whole of the Llŷn peninsula.

St Einion is credited with granting land at Penmon on Anglesey to his brother, Seiriol, for the founding of a monastery, and also land for Seiriol's hermitage on Puffin Island (Ynys Seiriol). He is also claimed as the founder of the first church building at Llanengan in Lleyn, although this is replaced by a new building around the late fifteenth century.

That name - Llanengan - name may originally be Llan-einion, which goes through various shifts which include Llan-eigneion, before it reaches its modern form. Hywel Rheinallt writes a poem in the fifteenth century which refers to Einion as a 'golden-handed prince of Lleyn'.

Lleyn peninsula
The expansion of Rhos to take in the Lleyn peninsula under the command of St Einion Frenin may have threatened the over-king of Gwynedd as a potential rival, a possible reason for it being merged back into Gwynedd proper by Rhun Hir in the mid-sixth century


With his apparently pious life, St Einion fails to produce an heir. However, a brother, Cynlas, has a son, Maig, who can succeed him. Despite this, it seems that Rhos loses any autonomy it may possess as its overlord, Rhun Hir of Gwynedd, draws the principality under his direct control.

Maig and his family appear to remain important lords in eastern Gwynedd after they cease to be ruling princes, but their names are shown here in grey to highlight their loss of power.

fl c.570s

Maig ap Cynlas

Son of Cynlas. Lord in eastern Gwynedd (Lord of Rhos?).

fl c.590s

Cyngen ap Maig

Son. Lord in eastern Gwynedd (Lord of Rhos?).

fl c.600s

Cadwal Cryshalog

Son. Lord in eastern Gwynedd (Lord of Rhos?).


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).

Map of Britain AD 550-600
At the start of this period, the Angle and Saxon kingdoms on the east and south coasts were firmly established. Many of the rapidly-formed Romano-British territories in those areas had been swept away in the late fifth century (click or tap on map to view full sized)

FeatureIago ap Beli of Gwynedd and Selyf of Powys are both killed, and the battle is a disastrous British defeat. As lords of Gwynedd, Isaag ap Einion of Dunoding, Idris Gawr of Meirionnydd, and Cadwal Cryshalog of Rhos would also be expected to involve themselves with their own bands of warriors (see one of Geoffrey of Monmouth's more accurate entries about this campaign via the feature link).

fl c.620s

Idgwyn ap Cadwal

Son. Lord in eastern Gwynedd (Lord of Rhos?).

fl c.670s

Einion ap Ifgwyn

Son. Lord in eastern Gwynedd (Lord of Rhos?).

fl c.690s

Rhufon ap Einion

Son. Lord in eastern Gwynedd (Lord of Rhos?).

fl c.720s

Hywel ap Rhufon

Son. Lord in eastern Gwynedd (Lord of Rhos?).

fl c.740s

Meirchion ap Hywel

Son. Lord in eastern Gwynedd (Lord of Rhos?).


Caradog ap Meirchion is a ninth generation descendant of Cynlas Goch. Now with the death of his overlord, Rhodri Molwynog, he is able to seize the throne and pronounce himself Prince Caradog ap Meirchion of Gwynedd.

754 - 798

Caradog ap Meirchion

Son. Ruler of Rhos and Gwynedd. Killed in battle.


Caradog is killed in battle by 'Saxons' in Snowdonia. These are presumably the half-Welsh, half-Angles of Mercia who are being led by Coenwulf. Caradog's son, Hywel ap Caradog, appears to continue to govern in Rhos.

The mountains of North Wales provided a powerful refuge for the rulers of Gwynedd in times of trouble but they still had to fight for victories to maintain that refuge, and Caradog ap Meirchion paid for this with his life

798 - 825

Hywel ap Caradog

Son. Ruler of Rhos. Sometimes wrongly attributed to Manau.


Hywel fights Cynan Tyndaethwy for control of Mon (Anglesey). The battle may be part of an attempt to regain or hold onto his ancestral lands there, and he apparently wins, as he holds Mon for about three years. The Rhos pedigree from Harleian Ms 3859 terminates with Hywel, leaving his successors a matter of some guesswork. One theory places the fifth century Caradog Freich Fras of Gwent here as Hywel's son.

At the time of the Anglo-Norman conquest of Wales in 1283, Rhos is organised into the lordship of Denbigh along with Rhufoniog. In the modern age both form part of the county of Denbighshire.

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