King Penda should also be remembered for his efforts to conquer the neighbouring kingdom of East Anglia.
The Venerable Bede records his invasion of East Anglia around the year 640 when Penda killed both Ecgric and the former king and now monk Sigeberht. Penda was to return again in 654 when he defeated and killed Anna and it was only then that Penda was able to force his will upon the East Angles through his ally and conspirator Aethelhere.
It was this last act that was the trigger for the conflict against Northumbria and brought Penda to that fateful meeting with Oswiu at the River Winwaed on the 15th November 654.