Despite his constant struggles with his kinsmen, Owain seldom lost sight of this object, and the prowess of his sons, Howel and Cynan, ably seconded his efforts. In 1147 Owain lost his favourite son Rhun; but the ‘insufferable sorrow’ into which this calamity threw him was soon ‘turned to sudden joy’ by the news of the capture of Gwyddgrug (Mold). ‘And when Owain our prince heard of this, he became relieved of all pain and from every sorrowing thought, and recovered his accustomed energy’ (Brut y Tywysogion, p. 172). In 1148 Owain built a castle in Yale, very near the English border. Both Randulf, earl of Chester, and Madog ap Maredudd [q. v.], prince of Powys, resented this, and in 1149 Madog joined with the earl to attack Owain, but was signally defeated at Counsillt. But Owain's power was still diminished by family feuds. In 1149 he was forced to imprison his son Cynan. In 1151 he drove his brother Cadwaladr from his refuge in Anglesea, and blinded and mutilated his brother Cadwallon, and his nephew, Cadwallon's son, Cunedda. Such vigorous and bloodthirsty measures secured his hold more firmly over Gwynedd. In 1155 he was able to lead an expedition against Ceredigion.
Henry II had now succeeded to the English throne, and put down the anarchy of the last reign. Cadwaladr and Madog urged him on to resist the successful aggressions of Owain Gwynedd, and in July 1157 there took place Henry's first expedition against North Wales. While the English army encamped on the frontier of Cheshire, Owain and his sons took up their position at Basingwerk, which they fortified with entrenchments (ib. p. 184). The dark wood of Cennadlog separated the two armies. Henry sent part of his army by the coast, while the rest threaded the dense forest. But the sons of Owain attacked the English amidst the wood with such success that Henry of Essex, the constable, dropped the king's standard and fled in despair. The king, however, rallied his troops, and successfully pushed through the wood; whereupon Owain fled from Basingwerk to a place called Cil Owain, while Henry II occupied Rhuddlan, and sent the fleet to land the second army in Anglesea. The English suffered severely, but Owain was in great danger of being crushed between the fleet and the army. Neither party was in a condition to push matters to extremities, so that peace was easily patched up. Owain performed homage to Henry as his liege lord, surrendered hostages as a pledge of his future loyalty, and restored Cadwaladr, Henry's ally, to his former territory. The English boasted that the Welsh were subdued to the English king's will, but Henry's expedition was no very brilliant success, and Owain's power was as strong as ever, as soon as the English host had recrossed the Dee (Gervase, i. 165–6; Will. Newb. in Howlett's Chron. Stephen, Henry II, and Richard I, i. 107-9; Robert of Toriqhi in ib. iv. 193; Brut y Tywysogion, pp. 186–8; Annales Cambr. pp. 46–7; Gir. Cambr. Itin. Will. in Opera, vi. 130, 137. Miss Norgate's good modern account of the expedition is only vitiated by her partial reliance on the so-called ‘Caradoc of Llancarvan,’ really Powel's sixteenth-century ‘History of Cambria’).
In 1159 Owain's son Morgan was slain by craft; but the next few years were a period of comparative peace, as his nephew Rhys ab Gruffydd [q. v.], commonly called the Lord Rhys, prince of South Wales, now attracted most of the English attention through his vigorous resistance to the marchers in South Wales. Owain himself seems to have been on the side of the French against his South-Welsh rival, and his brother Cadwaladr and his sons Howel and Cynan actually fought with the Earls of Chester and Clare against the Lord Rhys (Brut y Tywysogion, p. 194), while Owain handed over a Welsh prisoner to the marchers (ib. p. 194). In 1162 Owain was engaged in war with Howel ap Ieuav, lord of Arwystli, who got possession of the castle of Talawern in Cyveiliog through treachery (ib. p. 196). But Owain invaded Arwystli, and his ‘insupportable sorrow’ for the loss of the castle was changed to ‘sudden joy’ when his army almost annihilated the forces of his rival and went home with a vast booty. In 1163 he had the satisfaction of seeing Henry direct his second Welsh expedition against Rhys and the South-Welsh; but the complete triumph of the invading army seems to have tightened the bonds that bound Owain to his overlord. It was through Owain's intervention that his nephew Rhys was induced to make his submission to Henry II at Pencader (Gir. Cambr. Opera, viii. 216). In the summer of 1164 Owain appeared at the council of Woodstock along with his nephew Rhys and some of his chief nobles, where, on 1 July, they all renewed their homage to Henry (Ralph de Diceto, i. 311).
The restless chieftain did not, however, long keep the peace. In 1165 both Owain and his nephew Rhys of South Wales had renewed their plundering inroads (Robert of Torigny in Howlett iv. 222). In this year Owain's son Davydd [see Davydd I] devastated Englefield, the district between the Clwyd and Chester, and removed the