Cadwallon continued his ruinous invasion of Northumbria, however. Bede says that Osric besieged Cadwallon "in a strong town", but Cadwallon successfully "sallied out on a sudden with all his forces, by surprise, and destroyed him [Osric] and all his army."
The year in which he and Eanfrith ruled was subsequently deemed so abhorrent because of their paganism that it was decided to add that year to the reign of the Christian Oswald of Bernicia, who defeated Cadwallon and came to rule both Bernicia and Deira, so as to ignore the brief reigns of Osric and Eanfrith.