King of East Anglia 654-654
Since Aethelhere became king on the occasion of his brother Anna's death at the hands of the Mercian Penda and later was to fight at Penda's side, it is only to be presumed that he plotted with Penda to contrive his brother's death and place himself on the throne.
If this was so, Aethelhere was not to enjoy the fruits of his crime for long. Together with his fellow regicide Penda he challenged the might of king Oswiu of Northumbria at the Battle of the River Winwaed, and there both Penda and Aethelhere met their end on
the 15th November of the year 654.
The Venerable Bede - Historia Ecclesiastica Gentis Anglorum
The Anglo-Saxon Chronicle