In 655, in an early engagement that firmly established Anglo-Saxon paganism in Britain, the forces of King Penda of Mercia triumphed at the Cock Beck in present-day Yorkshire.
Glorious Mercian Victory at the Battle of WinwaedFresh from his successful campaign in Northumbria, he had gathered allies from East Anglia and Wales marching south with a large force led by "thirty warlords". Their opponent was Oswiu of Bernicia, the brother of Oswald of Northumbria who had fallen to defeat at the hands of the Mercians in the early battle of Maserfield.
The battle was fought by the river in the midst of heavy rains, and many more were drowned in the flight than destroyed by the sword. The result consolidated Mercian ascendancy over the Northumbria.