Powys Wenwynwyn and Gwynedd became bitter rivals in the years that followed, with the former frequently allying itself with England to further its aims of weakening the latter.

He did not return to Wales until 1241 after the death of Llywelyn and when he was invested with the lordships of Arwystli, Cyfeiliog, Mawddwy, Caereinion, Ystrad Marchell and Upper Mochnant by Henry III.

("Under the name and tenure of the free baronage of England, by resigning together with his heirs to the Lord the King and the Crown of England the princely name and coronet") The date should be accepted with reserve because Owen did not succeed his father in possession until 1286: it is possible that Owen was acting on behalf of his father, who was by then an old man.

From about that time, the former princely family began using the Normanised surname "de la Pole" instead of Welsh patronymics.

When Griffith de la Pole died without heirs in 1309, the lordship was then inherited (according to English law) by his sister Hawise "Gadarn" ("Hawise the Strong", often simply referred to as "The Lady of Powis"), rather than to the male heirs (as prescribed by Welsh law).

She died in 1349 and on the death of her husband John Charleton, 1st Baron Cherleton in 1353, the lordship passed to their children and thence out of native Welsh hands.