Penda, the king of Mercia and the Welsh king, Cadwalader, invaded the Christian kingdom of Northumbria in 633 and killed King Edwin at the Battle of Heathfield. He invaded Northumbria again in 642 where he defeated and killed King Oswald. Penda also made inroads into Wessex and East Anglia before being killed by King Oswiu of Northumbria at Winwaed in 655.