Powys Wenwynwyn or Powys Cyfeiliog was a Welsh kingdom which existed during the high Middle Ages. The realm was the southern portion of the former princely state of Powys which split following the death of Madog ap Maredudd of Powys in 1160: the northern portion (Maelor) went to Gruffydd Maelor and eventually became known as Powys Fadog; while the southern portion (Cyfeiliog) going to Owain Cyfeiliog and becoming known, eventually, as Powys Wenwynwyn after Prince Gwenwynwyn ab Owain, its second ruler. Powys Wenwynwyn and Gwynedd became bitter rivals in the years that followed, with the former frequently allying itself with England to further its own aims of weakening the latter. Princes of Powys Wenwynwyn 1160–1195 Owain Cyfeiliog married a daughter of Owain Gwynedd and abdicated in 1195. 1195–1216 Gwenwynwyn ab Owain Gwenwynwyn seized the cantref of Arwystli in 1197, when he was aligned with England. Following the marriage of Llywelyn the Great and Joan of England in 1208, warfare broke out once more between Gwenwynwyn and Llywelyn. In 1212 Gwenwynwyn's ancient royal seat at Mathrafal was destroyed and he was evicted from his territories. He changed allegiance again and was restored to his realm in 1215, making a new capital at Welshpool. In 1216 he was defeated in battle with the forces of Llywelyn and fled to England, where he died shortly afterwards. He was succeeded by his son. 1216–1286 Gruffydd ap Gwenwynwyn Gruffydd ap Gwenwynwyn spent his youth in England, maintained by King Henry III of England. 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. At some time before this he married Hawise, daughter of John Le Strange of Knockin. He transferred his allegiance back to Llywelyn ap Gruffudd in 1263 before returning to England's protection again after 1276, following a failed plot to murder Prince Llywelyn in collusion with his rival's own brother, Dafydd ap Gruffydd. His forces, commanded by his son Owain ap Gruffydd ap Gwenwynwyn, mobilised during the Welsh War of 1282–1283 with those of John Le Strange and Hugh le Despenser and it was their soldiers who ambushed and killed the last native Prince of Wales near Builth in 1282. End of the Principality Owain ap Gruffydd ap Gwenwynwyn (alias Owen de la Pole) allegedly surrendered the principality of