The evidence for Osbald's continued ambition is a letter that Alcuin wrote to him, probably in 798, in which Alcuin attempted to dissuade Osbald from further interventions in Northumbrian affairs.
A proba que demostra que o deposto Osbald seguía a ter ambición é unha carta de Alcuíno, probabelmente escrita no ano 798, na que intenta disuadir a Osbald de volver a intervir nos asuntos de goberno de Northumbria.