King of East Anglia 631-c635?
Sigeberht was the son of Raedwald and brother of Earpwald who fled to the sanctuary of Gaul when the pagan Ricberht usurped the throne of East Anglia but returned to take his rightful place as king.
He was described by the Venerable Bede as "a most Christian and learned man" and was responsible for returning the East Angles to the faith of Christ.
It is from the Venerable Bede that we learn that Sigeberht yielded the crown to his cousin Ecgric and retired to follow a monastic life. But Sigeberht was not to be allowed to enjoy the contemplative life that he desired, as Penda king of the neighbouring Mercians came with an army. The fearful East Angles dragged poor Sigeberht from his monastery and forced him to join them in battle, believing that the presence of the saintly Sigeberht would inspire them to victory over the pagan Penda. But all to no avail as Penda's army slaughtered the East Anglians and slew both Ecgric and Sigeberht.
It is unfortunate that the Venerable Bede fails to relate the exact dates at which these latter events occured and thus we cannot be certain when Sigeberht either abdicated or died.
The Venerable Bede - Historia Ecclesiastica Gentis Anglorum
The Anglo-Saxon Chronicle