The origins of Dyfed lie in the Roman civitas of the Demetae with its capital at Maridunum Demetarum or modern Carmarthen which was itself of course based on the old tribal territory of the Demetae whose origins stretch back well before the time of the Romans.
One of the Medieval kingdoms of Wales, at its largest extent Dyfed extended from Pembrokeshire, across Ystrad Tywi to the Gwyr peninsula. Ystrad Tywi was lost to Ceredigion in around 800, and Gwyr was finally lost to Morgannwg. Peristed as an independent kingdom until sometime after the year 904 when it was subsumed by Hywel Dda within his new creation of Deheubarth.
Rulers of Dyfed
The foundation of Dyfed
There is an Irish tradition that the tribe of the Deisi were forced into exile by the Irish High King after the failure of their rebellion. A medieval Irish tale, the Expulsion of the Deisi talks of;
Eochaid son of Artchorp, with his descendants, went over the sea into the land of Dyfed, and his sons and grandsons died there.
There is also an entirely separate Welsh
tradition that places Eochaid Allmuir
as one of the ancestors of the kings of Dyfed, and refers to his grandson Triffyn Farfog
, 'Triffyn the Beared' married a convenient heiress and thereby became recognised as king.
The one early king of Dyfed for whom we can be reasonably certain is Vortipor otherwise known as Gwrthefyr, who is identified with Vortiporious, the 'tyrant of Demetia' mentioned by Gildas in his De Excidio Britanniae. A memorial stone dated to the sixth century has also been discovered at Castell Dwyran, inscribed in Latin dedicated to a memoria Voteporicus protictoris , that is 'in memory of Vortipor protector' with a matching Ogham inscription to 'Vortecorigas'
Given the relatively high number of memorial stones found with Irish (that is Ogham) inscriptions in the south-west it seems unquestionable that Dyfed was subject to substantial Irish settlement and that its rulers shared some kind of Irish origin with Brycheiniog.
The connection with Brycheiniog was to be a recurring theme throughout the history of Dyfed; Cloten ap Nowy in the mid seventh century became ruler of both kingdoms, and future rulers of Dyfed and its successor kingdom Deheubarth all seem to have automatically assumed some kind of influence over Brycheiniog to the east.
At some point in time, Seisyll ap Clydog the ruler of the neighbouring kingdom of Ceredigion succeeded in seizing control of the territory of Ystrad Tywi from Dyfed; the enlarged Ceredigion became known as Seisyllwg after king Seisyll and the truncated Dyfed became known as Rheinwg after its king Rhein.
The trouble is that there are two kings named 'Rhein' to choose from, the probably early 8th century Rhein ap Cadwgan and the later Rhein ap Maredudd - opinion is also divided as to when exactly Seisyll ap Clydog reigned in Ceredigion. The most likely scenarios is to place this event firmly in the reign of the later Rhein ap Maredudd around the year 800.
In any event Seisyllwg itself succumbed to the assaults of the sons of Rhodri Fawr in the early ninth century where Cadell ap Rhodri seems to have been able to impose himself upon Ceredigion at the very least.
The ninth century gap
No one is quite sure what was happening in Dyfed in the middle of the ninth century as there is no real mention of any ruler of Dyfed. After the death of Triffyn ap Rhein in 814 there is no indication of who is in charge until the appearance of Hyfaidd ap Bledrig at the court of Alfred of Wessex in the 880s requesting assistance in resisting the inroads of Cadell ap Rhodri and his brothers.
From the Annales Cambriae we know that Coenwulf of Mercia ravaged Dyfed in 818 as part of his great push into Wales and thus the kingdom may have been destabilised. The only clue the Annales Cambriae provides is a reference for the year 860 to the expulsion of one 'Catgueithen' and a record of his death for the year 882.
However since Dyfed bears the highest concentration of Norse or Viking place names in Wales and there is therefore a suspicion that the kingdom may well have fallen under Viking control during the missing half century or so.
Hyfaidd is remembered as 'one of the three kings who sprang from villeins' as his father is known as Bledrig Aillt, or Bledrig 'the foreigner'; that is, he was no one in particular, and seems to have had no connection with the previous Demetian dynasty. Nothing is known of Bledrig Aillt, for all we know he may himself have been of Viking descent. He would not be the first or last ruler of Wales to have some kind of Norse connection were that to b ethe case.
The last rulers of Dyfed
Hyfaidd ap Bledrig succesfully transmitted the kingdom to his son Llywarch ap Hyfaidd who was in turn succeeded by his son Rhodri on his death in 903. Rhodri, if he did indeed rule, did no last long. In 904 he was beheaded in Arwystli according to the Annales Cambriae, although why and by whom we are not told.
Dyfed ended up in the hands of 'Hywel ap Cadell;, better known as Hywel Dda who was king of neighbouring Ceredigion/Seisyllwg which he had inherited from his father the previously metioned Cadell ap Rhodri. Hywel was to christen this new political entity of Dyfed including both Ceredigion and Ystrad Tywi as Deheubarth, the 'kingdom of the south'.
The Annlaes Cambriae
The Brut y Tywysogion
John Davies A History of Wales (Allen Lane, 1993)
Kari Mundi The Welsh Kings (Tempus, 2000)