Battle of the Winwaed: Penda of Mercia is defeated by Oswiu of Northumbria.

The Battle of the Winwaed was fought on 15 November 655 between King Penda of Mercia and Oswiu of Bernicia, ending in the Mercians' defeat and Penda's death. According to Bede, the battle marked the effective demise of Anglo-Saxon paganism.

Penda was a 7th-century king of Mercia, the Anglo-Saxon kingdom in what is today the Midlands. A pagan at a time when Christianity was taking hold in many of the Anglo-Saxon kingdoms, Penda took over the Severn Valley in 628 following the Battle of Cirencester before participating in the defeat of the powerful Northumbrian king Edwin at the Battle of Hatfield Chase in 633.

Oswiu, also known as Oswy or Oswig, was King of Bernicia from 642 and of Northumbria from 654 until his death. He is notable for his role at the Synod of Whitby in 664, which ultimately brought the church in Northumbria into conformity with the wider Catholic Church.

November 15 is the 319th day of the year in the Gregorian calendar; 46 days remain until the end of the year.