He succeeded his father in 909 as King of Deheubarth. The Gwentian Chronicle records that "Anarawd son of Rhodri the Great, king of the Britons" died in 913 and then "Hywel son of Cadell ruled over all Wales". The Chronicle of the Princes of Wales records that "Rhys son of Tewdwr began to reign" in 1077. Gerald of Wales´s Descriptio Kambriæ records the descent of the rulers of South Wales in reverse chronological order as follows: “...Theodorus filius Cadelh, Cadelh filius Eneæ, Eneas filius Oenei, Oeneus filius Hoeli da, id est Hoeli boni, Hoelus filius Cadelh, Cadelh filius Roderici magni”. he Chronicle of the Princes of Wales records that "king Howel the Good, son of Cadell, went to Rome" in 926.
King of Gwynedd. Athelstan King of Wessex agreed the frontier with the Welsh princes along the river Wye at a meeting in Hereford in , exacting a heavy tribute from them. Hywel visited Athelstan King of Wessex many times between 931 and 937, and was influenced by English life and methods of government. [The Gwentian Chronicle records that "Eidwal the Bald, son of Anarawd being dead, Hywel took upon himself the government of all Wales" in 943. The Annales Cambriæ record the death in 950 of "Higuel rex Brittonum". The Chronicle of the Princes of Wales records that "Howel the Good, son of king Cadell, chief and glory of all the Britons" died in 948. [The Gwentian Chronicle records that "Hywel the Good, son of Cadell king of all Wales" died in 948. 1
HYWEL DDA ( Hywel the Good ) (d. 950 ), king and legislator. He was generally called 'Hywel the Good, son of Cadell, prince of all Wales,’ and in ‘Brut y Tywysogion’ he is called ‘the head and cynosure of all the Britons.’ He is the only Welsh prince to have been called ‘the Good.’ He was b. towards the end of the 9th cent. but the place of his birth is unknown.
Cadell was one of the sons of Rhodri the Great, and his inheritance was the southern part of his father's principality, namely Seisyllwg (Ceredigion and Ystrad Tywi). He bequeathed this to his two sons Hywel and Clydog, and on the latter's death in the year 920 Hywel took possession of the whole. He m. Elen, daughter of Llywarch ap Hyfaidd of Dyfed, who brought him Dyfed (modern Pembrokeshire ) as her dower — for Llywarch was, in all probability, the last prince of Dyfed. The prince of Gwynedd was Idwal Foel who also probably ruled over Powys. Idwal was killed in battle with the English in the year 942 and, although he had sons, Hywel took possession of all his territory. He thus became ‘king of all Wales ’ although Morgannwg and Gwent continued to have independent sovereigns.
He succeeded throughout his life in maintaining peace with the English kings by submitting to them. In 918 he, Clydog his brother, and Idwal Foel did homage to Edward , son of Alfred the Great , and about 926 he and Owain of Gwent journeyed to Hereford to acknowledge the overlordship of Athelstan . His name is frequently mentioned in the English charters as a vassal king and there is little doubt that from time to time he visited the Wessex court . For all that, he was sufficiently independent to mint his own silver pennies and, as far as is known, he is the only Welsh prince to have done this.
His pilgrimage to Rome in 928 was one of the outstanding incidents in his life. It has been suggested that in this respect he was only following Alfred 's example and it may well be that it was Alfred 's work in England which induced him to undertake his most important task, the codification of the jumble of laws and customs prevailing in his kingdom . There can be no doubt that he was confirmed in his resolution by what he had seen on his travels.
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 ‘Ty Gwyn ar Daf in Dyfed,’ (later on, an abbey was to rise near the spot and the Welsh name for the village of Whitland is still ‘ Yr Hen Dy Gwyn.’) This took place some time between 942 and 950 — perhaps about 945 .
Hywel d. in 949 or 950 ; Harl. MS. 3859 enters it under the year corresponding to 950. 2