Hywel was born about 900 AD and died about 950, the place of his

birth is unknown. He was the grandson of Rhodri Mawr or

Rhodri the Great, who in  856 defeated the invading Danes in

Ynys Mon or Anglesey.

He was a king and a law maker, he was called Hywel Dda (the Good), Prince of all Wales

and in the Brut y Tywysogion he is called ‘the  head and cynosure of all the Britons”

His grandfather was Rhodri the Great who was King of all Wales.  When Rhodri died

Hywel’s father Cadell inherited Seisyllwg(Ceredigion and Ystrad Tywi). 

When Cadell died the kingdom of Seisyllwg was divided between his 2 sons, Hywel and Clydog. However Clydog died in 920 and Hywel tool charge of the whole kingdom.

When he married Elen, daughter of Llywarch ap Hyfaidd King of

Dyfed , Hywel became the ruler of Dyfed and therefore became took controlof the greater part of south west Wales.

When his cousin, Idwal Foel (another grandson of Rhodri the Great) was killed, Hywel

took control of Gwynedd and Powys, thereby ruling the whole of Wales, with the exception of Morgannwg and Gwent.

Gwlad Nini, being on the border between Morgannwg and Ystrad Tywi, was fought over and conquered several times during this period.

Hywel maintained peace with the English by submitting to them, however he maintained enough independence to mint his own coinage.

Hywel is best remembered for the codification of the jumble of laws and customs prevailing in his kingdom.

“The earliest extant manuscript of the ‘ Laws of Hywel the Good ’ dates from the last quarter of the 12th cent , but all the manuscripts agree that the laws were framed by his command and under his authority. They agree, too, as to the method adopted by him for carrying out the undertaking, namely the summoning of six representatives from each commote in his principality to a great conference at ‘Tŷ Gwyn ar Daf in Dyfed,’ (later, an abbey was to rise near the spot and the Welsh name for the village of Whitland is still ‘Yr Hen Dŷ Gwyn.’) This took place some time between 942 and 950— perhaps about 945 ...Hywel’s law was responsible for the consciousness of national unity prevalent among the Welsh of the Middle Ages.”  Williams, National Library of Wales on line Biographies 37

Under Hywel’s Law on a landowner's death his land was to be shared equally between his sons, legitimate and illegitimate. This caused conflict with the church, as under canon law illegitimate children could not inherit. It was also different from English law, where the eldest son inherited all.

There is evidence that the Law of Hywel Dda was still in effect in north Gower as late as 1338 when John de Mowbray II who had inherited Bramber and Gower confirmed to his tenants in subboscus all their ancient customs and laws, thereby confirming that the Welsh in Gower were still abiding by the Welsh Law or Rule of Hwyel Dda.

The Llys Nini Quit Claim of 1507, shows that Ieuan ap Gwilym Ddu’s lands were divided between 2 sons, Gwilym and Tomos (William and Thomas). This was possibly a division under Hywel’s Rule.

The Act of Union 1536 imposed English Law on Wales and Hywel’s Rule ceased.

In the latter part of his reign Hywel Dda had made  Dinefwr, near Llandeilo, his main base. There is no archaeological evidence to support this claim. The current castle, although built by his descendants post dates his death by hundreds of years.

Owain ap Hywel Dda, succeeded his father Hwyel in ruling south west Wales and launched attacks on Morgannwg, the territory to the east. Owain was possibly incapacitated in later life, as his son Einon ap Owain ap Hywel, led his war band and possibly ruled the kingdom for many years. Einon was killed in 983/4 and was succeeded by his brother Marududd ap Owain, who on Owain’s death became King.