By his time the kingdom must have reached the west coast, as he is said to have conquered the islands of Anglesea and Man.
When we turn to the British Islands we find, as we should expect, no traces of the Druids in England and Wales after the conquest of Anglesea mentioned above, except in the story of Vortigern as recounted by Nennius.
MENAI STRAITS, a channel of the Irish Sea, separating Anglesea from Carnarvonshire, N.
Coast of Anglesea; Bardsey (Ynys Enlli), near Braich-y-Pwll; and the islands of Ramsey, Grassholm, Skomer, Skokholm and Caldy (Ynys Pyr) off the Pembrokeshire coast.
The chief inlets are the mouth of the Dee, dividing Flint from Cheshire; the Menai Straits, separating Anglesea from the mainland; Carnarvon Bay; Cardigan Bay, stretching from Braich-y-Pwll to St Davids Head; St Brides Bay; Milford Haven; Carmarthen Bay; and Swansea Bay.
There are valuable copper mines in Anglesea, and lead.
The diocese of Bangor consists of the counties of Anglesea, Carnarvon and large portions of Merioneth and Montgomery.
The Decangi, owning the island of Anglesea (Ynys Fon) and the Snowdonian district; the Ordovices, inhabiting the modern counties of Denbigh, Flint and Montgomery; the Dimetae, in the counties of Cardigan, Carmarthen and Pembroke; and the Silures, occupying the counties of Glamorgan, Brecknock, Radnor and Monmouth.
At this period the copper mines of Mona or Anglesea, the silver mines near Plinlimmon and the gold mines in the valley of the Cothi in Carmarthenshire were exploited and worked with some success by the conquerors.
Like Alfred of Wessex, Rhodri also built a fleet in order to protect Anglesea, " the mother of Wales," so called on account of its extensive cornfields which supplied barren Gwynedd with provisions.
Consolidation of CambroBritish territory was found impossible; there was no settled capital; and the three princes fixed their courts respectively at Aberffraw in Anglesea, at Dynevor (Dinefawr) near Llandilo in Deheubarth, and at Mathrafal in Powys.
At the accession of William Rufus the domain of Gwynedd had been reduced to Anglesea and the Snowdonian district, and that of South Wales, or Deheubarth, to the lands contained in the basins of the rivers Towy and Teifi, known as Ystrad Tywi and Ceredigion.
Thus Anglesea, Carnarvon, Merioneth and Flint were erected in North Wales; whilst out of the districts of Ystrad Tywi and Ceredigion in South Wales, the old dominions of the house of Dynevor, the counties of Carmarthen and Cardigan were formed.
The Yorkist faction seems to have been strongest in the eastern portion of the Principality, where the Mortimers were all-powerful, but later the close connexion of the house of Lancaster with Owen Tudor, a gentleman of Anglesea (beheaded in 1461) who had married Catherine of France, widow of Henry V., did much to invite Welsh sympathy on behalf of the claims of Henry Tudor his grandson, who claimed the English throne by right of his grandmother.
The coast-line of Anglesea and the Isle of Wight, but of no other islands, is included.