This rests largely on a confused passage in Symeon of Durham's Historia Regum Anglorum, and it has more recently been suggested that the interpretation offered by Frank Stenton—that it is based on a textual error and that Óengus and Æthelbald were not associated in any sort of joint overlordship—is the correct one.
Isto baséase principalmente nunha confusa pasaxe da Historia Regum Anglorum de Simeón de Durham, e polo xeral considérase que a interpretación ofrecida por Frank Stenton (que está baseada nun erro textual e en que Óengus e Æthelbald non estaban relacionados en ningunha clase de reinado conxunto) é a correcta.