Gruffydd ab Gwenwynwyn from Powys, forcing the latter to take refuge in England, though the L'Estranges and other border families had already come to his help. Meanwhile a severe struggle had been proceeding in the south, and in Lent 1257 Llywelyn marched into Deheubarth (South Wales) to help his struggling allies there. He spent most of Lent on the borders of the Bristol Channel, burning the lands of the English lords of Kidwelly, Gower, and Swansea, and returning before Easter laden with booty to the north, after either subduing all the south Welsh or being accepted voluntarily as a deliverer. But on his departure some of the Welsh again joined the English, and the purposeless strife raged as before. Stephen Bausan, Edward's deputy, was slain in battle.
All the plans of Edward, whose father had been unable or unwilling to send him help, were shattered both in the east and north by Llywelyn's activity. In March 1257 Llywelyn entered into a league with the nobles of Scotland against Henry (Fœdera, i. 370). At last, in the summer of that year, Henry himself accompanied Edward in a formal expedition to North Wales, remaining in the country from 1 Aug. to 8 Sept. (Liber de Antiquis Legibus, p. 29; Matt. Paris, v. 639, 645, 648), and only advancing as far as Deganwy or Gannock. He never crossed the Conway, and therefore did not in effect invade Llywelyn's dominions at all. Henry lingered at Deganwy, hoping for the arrival of a large force of Irish light infantry, without whose support it would have been hopeless for the English men-at-arms to penetrate the trackless wilderness of Snowdon. But the Irish never came, and Henry, after strengthening the castles, returned to England, leaving the open country again the prey of Llywelyn's assaults. Llywelyn closely followed up the retreat of the king, cutting off stragglers (ib. v. 651). Next year the barons could not be persuaded to undertake a second campaign. In June 1258 a truce for one year was signed, reserving for Henry the right of communication with Diserth and Deganwy, and practically abandoning Perveddwlad to Llywelyn (Fœdera, i. 372). But almost immediately complaints arose of its violation (ib. i. 374, 377). The border struggle continued. Llywelyn still had to contend against rival Welsh chieftains and hostile marcher lords, though men were already marvelling how, despite the ancient animosities of north and south Wales, Llywelyn managed to bring the Welsh together under his sway (Matt. Paris, v. 645). Matthew Paris himself condemns the treachery of the marchers (ib. v. 717), and commends the vigour, courage, and patriotism of the Welsh prince. In 1258 a body of Welsh lords had bound themselves by oath to uphold Llywelyn. But one of them, Maredudd ab Rhys, soon went against him. Accordingly, at Whitsuntide 1259 Llywelyn, with the advice of his nobles, condemned Maredudd ab Rhys for treason, and imprisoned him until Christmas at Criccieth, when he was released on leaving his son a hostage and putting his stronghold of Dinevwr, the traditional capital of the south Welsh kings, into the hands of the lord of Gwynedd. At Michaelmas, Llywelyn sent the Bishop of Bangor to England on a vain attempt to make peace with the king (Flores Hist. ii. 435). In January 1260 Llywelyn overran the region round about Builth, and thence marched on a fruitless raid into the south, reaching as far as Tenby. Later on he took Builth Castle from Roger Mortimer, owing to the treachery of some of the garrison. On 30 July Mortimer was acquitted by the king of any blame in the matter (Fœdera, i. 398). After the dispute of king and barons had been settled by the Provisions of Oxford, summonses were issued on 1 Aug. for the feudal levies to assemble at Shrewsbury and Chester to fight against Llywelyn (ib. i. 398-9); while Archbishop Boniface of Canterbury threatened Llywelyn with excommunication if he did not make restitution for the lands he had conquered. But there was no solid result from these renewed threats. In August 1260 the divided English government consented to the renewal of the truce for two years. Llywelyn claimed under its provisions the right of carrying on war against all the marchers who refused to accept its conditions, without incurring the blame of violating his agreement with the king (Annales Cambriæ, p. 99).
After two years of comparative quiet the disputes were renewed early in 1262 (Fœdera, i. 414, 420). In July there was a rumour in England that Llywelyn was dead, and Henry summoned an army to meet at Shrewsbury (ib. i. 420). In November some Welsh subjects of Roger Mortimer in Melenydd rose in revolt, and called upon Llywelyn to protect them from the new castle of Cevnllys, which their English lord was building within their borders. Llywelyn came with an army, captured Cevnllys, Bleddva, and Cnwclas castles, and received the homages of the men of Melenydd (Annales Cambriæ, p. 100; Brut y Tywysogion, p. 349; Worcester Annals, p. 447). Thence he marched into the lordship of Brecon, where also he took oaths of fealty from the Welsh part of the population. Satisfied with this great extension of his power, he re-