King Oswald of Northumbria was a 7th-century ruler known for his significant role in the early Christianization of England. He became king around 634 AD after defeating the pagan king Cadwallon at the Battle of Heavenfield. Oswald was a devout Christian and worked to spread Christianity throughout his kingdom. Oswald is also remembered for his support of missionaries, particularly Aidan, who founded the monastery on Lindisfarne. His reign marked a period of stability and growth for Northumbria, but he was killed in battle in 642 AD, becoming a martyr and later a saint in the Christian tradition.