Cadwallon ap Cadfan (d. 634), King of Gwynedd, who held the Isle of Man for the last year of his life.

The Manx antiquaries set him against Edwin of Northumbria and cite Bede for the sequence. Edwin, following up his successes against Cadwallon, wrested the Island in 625 from the Scots who were then in possession of it. When Edwin was killed at the battle of Heathfield in 633, Cadwallon not only regained his own territories but gained the Isle of Man with them. He died the year after.

That is the whole of him in these sources. The alliance with Penda of Mercia against Edwin, and the wider British and Irish presence in the Irish Sea before the Norse came, are the setting the Manx writers assume rather than describe.