The sons of Griffith—Owen, Llywelyn, and David—at once took their uncle's place; and by 1255 Llywelyn ap Griffith was sole ruler. By that year Henry III. had given his young son Edward the earldom of Chester, which had fallen to the crown, and the lands between the Dee and the Conway, which he claimed by a treaty with the dead Griffith.Thus Edward and Llywelyn began their long struggle.
Between 1255 and 1267 Llywelyn tries to recover his grandfather's position in Wales. In 1255 his power extended over Gwynedd only. He found it easy to extend it over most of Wales, because the rule of the English officials made the Welsh chiefs long for the protection of Gwynedd. The Barons' War paralysed the power of the King, and Llywelyn made an alliance with Simon de Montfort and the barons.Even after Montfort's fall in 1265 the barons were so powerful that the King was still at their mercy. In 1267 Llywelyn's position as Prince of Wales was recognised in the Treaty of Montgomery. His sway extended from Snowdon to the Dee on the east, and to the Teivy and the Beacons on the south—practically the whole of modern Wales,except the southern seaboard. Within these wide bounds all the
