(c. 1223-1282). Prince of Gwynedd who took advantage of civil war in England to proclaim himself ‘Prince of Wales’ in 1258. By the Treaty of Montgomery in 1267, Edward I recognised this title, but failure to do homage to Edward led to Edward’s conquest of north Wales in 1277 and Llywelyn’s submission at the Treaty of Aberconwy. A new revolt against English dominance sparked by Llywelyn’s brother Dafydd led to Llywelyn’s death at Cilmeri in 1282.