Chapter XXIV. How when King Penda was slain, the province of the Mercians received the faith of Christ, and Oswy gave possessions and territories to God, for building monasteries, as a thank offering for the victory obtained. [655 A.D.]
pg. 189.
"After this he gave battle with a very small army: indeed, it is reported that the pagans had thirty times the number of men; for they had thirty legions, drawn up under most noted commanders. [...] King Oswald's son Oidilwald, who ought to have supported them, was on the enemy's side, and led them on to fight against his country and his uncle; though, during the battle, he withdrew, and awaited the event in a place of safety. The engagement began, the pagans were put to flight or killed, the thirty royal commanders, who had come to Penda's assistance, were almost all of them slain; among whom was Ethelhere, brother and successor to Anna, king of the East Angles. He had been the occasion of the war, and was now killed, having lost his army and auxiliaries. The battle was fought near the river Winwaed, which then, owing to the great rains, was in flood, and had overflowed its banks, so that many more were drowned in the flight than destroyed in battle by the sword."