After the withdrawal of the Romans in the 5th century the northern Britons seem to have shown greater determination in maintaining their independence than any of the southern kingdoms and, according to Welsh tradition, Cunedda, the ancestor of the kings of Gwynedd, had himself come from the north.
550 by the building of Maelgwyn Gwynedd, prince of North Wales.
The old British fort, Caer Drewyn, one of a chain of forts from Dyserth to Canwyd, is the supposed scene of Glendower's retreat under Henry IV., and here Owen Gwynedd is said to have prepared to repulse Henry II.
Of Llangollen, founded about 1200 by Madoc ab Gruffydd Maelor, lord of Dinas Bran and grandson of Owen Gwynedd, prince of Wales.
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.
In 877 Rhodri, after many vicissitudes, was slain in battle, and his dominions of Gwynedd (North Wales), Deheubarth (South Wales) and Powys (Mid Wales) were divided amongst his three sons, Anarawd, Cadell and Mervyn.
In Howel's code the prince of Gwynedd with his court at Aberffraw is recognized as the leading monarch in Wales; next to him ranks the prince of Deheubarth, and third in estimation is the prince of Powys.
The dissensions of the turbulent princes of Gwynedd, Powys and Deheubarth, and of their no less quarrelsome chieftains, now rent the country, which was continually also a prey to Saxon incursions by land and to Scandinavian attacks by sea.
Some degree of peace was, however, given to the distracted country during the reign of Llewelyn ap Seissyllt, the husband of Angharad, heiress of Gwynedd, who at length secured the overlordship or sovereignty of all Wales, and reigned till 1022.
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.
Griffith ap Cynan, of the royal house of Gwynedd, who had been first an exile in Ireland, and later a prisoner at Chester, once more returned to his native land, and defied the Norman barons with success, whilst Henry I.
The confused reign of Stephen was naturally favourable to the development of Cymric liberty, and with such strong princes as Owen, son of Griffith ap Cynan, heir to the throne of Gwynedd, and with Griffith ap Rhys ruling at Dynevor, the prospects of the Cymry grew brighter.
Peace was made with Owen of Gwynedd, the successor of Griffith ap Cynan, and with Rhys ap Griffith of South Wales.
In 1169 Owen Gwynedd died and was buried in Bangor cathedral after a reign of 33 years, wherein he had successfully defended his own realm and had done much to bring about that union of all Wales which his grandson was destined to complete.
At the castle of Cardigan in 1176, Prince Rhys held a historic bardic entertainment, or eisteddfod, wherein the poets and harpists of Gwynedd and Deheubarth contended in amicable rivalry.
This enlightened prince died in 1196, and as at his death the house of Dynevor ceased to be of any further political importance, the overlordship of all Wales became vested indisputably in the house of Gwynedd, which from this point onwards may be considered as representing in itself alone the independent principality of Wales.
The prince of Gwynedd henceforth considered himself as a sovereign, independent, but owing a personal allegiance to the king of England, and it was to obtain a recognition of his rights as such that Llewelyn ap Iorwerth, " the Great," consistently strove under three English kings, and though his resources were small, it seemed for a time as though he might be able by uniting his countrymen to place the recognized autonomy of Gwynedd on a firm and enduring basis.
He was succeeded by David II., at whose death without children in 1246 the sovereignty of Gwynedd, and consequently of Wales, reverted to his three nephews, sons of his half-brother Griffith, who had perished in 1244 whilst trying to escape from the Tower of London, where Henry III.
For after the battle of Evesham a treaty was concluded between the English king and the Welsh prince at Montgomery, whereby the latter was confirmed in his principality of Gwynedd and was permitted to receive the homage of all the Welsh barons, save that of the head of the house of Dynevor, which the king reserved to himself; whilst the four fertile cantrefs of Perfeddwlad, lying between Gwynedd and the earldom of Chester, were granted to the prince.
On Palm Sunday 1282, in a time of peace, David suddenly attacked and burnt Hawarden Castle, whereupon all Wales was up in arms. Edward, greatly angered and now bent on putting an end for ever to the independence of the Principality, hastened into Wales; but whilst the king was campaigning in Gwynedd, Prince Llewelyn himself was slain in an obscure skirmish on the 11th of December 1282 at Cefn-ybedd, near Builth on the Wye, whither he had gone to rouse the people of Brycheiniog.
Having suppressed the independence of Wales, Edward now took steps to keep Gwynedd itself in permanent subjection by building the castles of Conway, Carnarvon, Criccieth and Harlech within the ancient patrimony of the princes of North Wales, whose legitimate race was now extinct save for Llewelyn's daughter Gwenllian, who had entered the convent of Sempringham.
Glamorgan and the county palatine of Pembroke had hitherto been the only portions of the country subject to English shire law, but now Edward parcelled out the ancient territory of the princes of Gwynedd and of Deheubarth into six new counties, with sheriffs, coroners and bailiffs.
It would be well-nigh impossible to exaggerate the services rendered to the ancient British tongue, and consequently to the national spirit of Wales, by these Elizabethan and Jacobean translations, issued in 1567, 1588 and 1620, which were able definitely to fix the standard of classical Welsh, and to embody the contending dialects of Gwynedd, Dyfed and Gwent for all time in one literary storehouse.
Mold Castle was probably built by Robert Monthault (temp. William Rufus), was taken and destroyed by Owen Gwynedd in 1144-1145, its site lost to the English and retaken by Llewelyn ap Iowerth in 1201, and by Gruffydd Llwyd in 1322.