Cadwallon

Cadwallon (d. 634), king of Gwynedd. With his ally Penda of Mercia, Cadwallon was responsible for the death of Edwin of Northumbria at the battle of Heathfield in 633 and for those of his successors Osric of Deira and Eanfrith of Bernicia the following year. In 634 he was himself defeated by Eanfrith's brother Oswald at the battle of Heavenfield, near Hexham.