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Celtic Kingdoms of the British Isles

Celts of Cymru


Guorthegirnain / Gwrtheyrnion (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'.

The tiny region of Guorthegirnain was located in central Wales, between Buellt to the south and Powys to the north. As far as early Welsh tradition will reveal, it would seem to have been part of Vortigern's ancestral lands which emerged into highly tenuous history in the form of the Paganes territory at the start of the fifth century AD.

FeatureThe region bears Vortigern's name in its Welsh form - Gwrtheyrnion (or Gwerthrynion, the modern spelling), which was rendered into Latin for the Historia Brittonum (see feature link) as Guorthigirniaun or Guorthegirnain (the latter is sometimes shown as ending in an 'm' - Guorthegirnaim - but this would never have happened, so it could be a transcription error, either by earlier clerics or modern scholars). Gwrtheyrnion's key town was Rhaeadr Gwy (perhaps better known as Rhayader). This later formed the county town of Sir Faesyfed (the historic county of Radnorshire, today part of Powys).

Although detail about Vortigern is hard to come by, and is open to much speculation, it seems likely that he became the supreme authority in post-Roman Britain by about 425. Tradition states that he subsequently devolved authority in the land of the Paganes to his sons, handing each of them control of a portion in the form of Gwent, Buellt, and Guorthegirnain. His second son, Cadeyrn Fendigaid, succeeded him in the Paganes territory itself, ruling in his name during much of his lifetime.

Guorthegirnain seems to have been governed entirely by Buellt and was subject to its rule. Normally that would suggest that the son of Vortigern who inherited Guorthegirnain either did not survive long or did not produce an heir to inherit his territory, but in this case the son who held Buellt was the same one who held Guorthegirnain: Pascent. So however it happened in detail, Buellt's rulers were Guorthegirnain's rulers, and all of them could trace their descent to Vortigern.

Unfortunately, information on the region is extremely patchy. In its early days it seems to have been regarded as a principality. By the time that charters and the like were being signed it often appears as a cwmwd (or cymwd in those early documents). This was a later, smaller sub-division of the original smallest unit of territory, the cantref. The medieval Middle Welsh form of this word, was cymwt which transferred into English as 'commote', used to refer to a secular division of land rather than a principality.

Roman Canterbury

(Information by Peter Kessler, with additional information by Edward Dawson, from A History of Wales from the Earliest Times to the Edwardian Conquest, John Edward Lloyd, 1912, from The Description of Penbrokshire, George Owen (Volume 3 Issue 1 of the Cymmrodorion record series), from the Historia Brittonum (The History of the Britons), Nennius (J A Giles, Ed & Trans, 1841, published as part of Six Old English Chronicles (Henry G Bohn, London, 1848)), from the Life of St Germanus of Auxerre, Constantius of Lyon, from History of the Kings of Britain, Geoffrey of Monmouth, from Welsh Genealogies AD 300-1400, Peter Bartrum, and from External Link: The Definitive Guide To Builth Wells.)


The principality of Guorthegirnain seems to have been formed by now, and possibly as early as AD 425 or so, when Vortigern is presumed to devolve regional authority to his sons while he governs the island of Britain.

The minor district of Maelienydd is also formed, although perhaps a little later. This consists of what seems to be a cantref - a standard division of territory - which is detached from the Paganes. Guorthegirnain borders it to the west and the Paganes surrounds it to the north, east (truncated by Offa's Dyke about three hundred years later), and south.

The history of Guorthegirnain - later Gwrtheyrnion - in central Wales prior to the early modern period is shrouded in mist, with only a few brief glimpses of half-seen events


FeatureBy now the newly arrived Jutish foederati have seen how weak are the British defences and begin a takeover of the kingdom of Ceint, aided by the many older foederati settlements in key areas of the land (see feature link).

As the east of the island is engulfed by the chaos of the foederati revolt, later tradition (mostly contained within the Historia Brittonum) states that the leading Briton, Vortimer, is poisoned while Vortigern flees to the province of Guorthegirnain, so called from his own name, where he conceals himself with his wives.

St Germanus follows him with all the clergy of the British Church, and upon a rock prays for his sins during forty days and forty nights. Vortigern returns to battle briefly before fleeing again and being put to death by Ambrosius Aurelianus.

c.455 - c.760

One of the results of the messy situation in the east and the death of Vortigern is that Guorthegirnain now passes to his sole surviving (legitimate) son. Nennius states that this is 'granted' by Ambrosius Aurelianus, but it is probably little more than a rubber stamp.

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)

Pascent governs the principality directly from Buellt, although he has probably already exercised regional control over it from the point at which it had first been divided from the Paganes. In fact, it would seem that Pascent is already deceased by this time and that it is his son, Braciat, who now governs Buellt and Guorthegirnain - a fine detail which may be lost to some chroniclers.

by 800

The fate of the last king of Builth (Buellt) is unknown, as are any firm dates for his life and reign. A rough estimate is that he is dead by AD 800. Afterwards, Builth and Gwrtheyrnion (Guorthegirnain) cease to exist as separate Welsh territories in their own right, being absorbed by Seisyllwg and then Deheubarth.

MapThe precise circumstances and process by which this happens are unknown (see map link). They re-emerge in the tenth century as parts of the political formation known as Rhwng Gwy a Hafren which soon becomes part of the Welsh Marches. In the sixteenth century Gwrtheyrnion becomes part of the new county of Sir Faesyfed (Radnorshire) before being absorbed into the county of Powys in the modern age.

River Wye
One of the longest rivers in Britain, the River Wye (Afon Gwy in Welsh) ran along the eastern edge of Buellt, dividing it from Powys on the other side

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