Bleddyn ap Cynfyn was a Welsh prince who lived during the 11th century. He was a member of the royal house of Gwynedd and the son of Cynfyn ap Gwerystan. Bleddyn is known for his role in the political landscape of Wales, particularly during the struggles for power among various Welsh kingdoms. He became the king of Gwynedd after the death of his cousin, Griffith ap Cynan, and ruled alongside his brother, Rhiwallon ap Cynfyn. Bleddyn's reign was marked by efforts to unify the Welsh territories and resist the encroachment of the Normans. His legacy is significant in the history of medieval Wales.