Edwin was born in 585, the son of King Aelle of Deira. In 604, King Aethelfrith of Bernicia deposed his uncle Aethelric of Deira, and Edwin was forced to go into exile at the court of King Cadfan ap Iago in Gwynedd and then at the court of King Raedwald in East Anglia. In 616, Aethelfrith invaded East Anglia after Raedwald refused to hand over Edwin, only to be killed in battle on the banks of the River Idle. Edwin was installed as King of Bernicia and Deira by Raedwald, who became bretwalda, forcing Aethelfrith's sons to go into exile in Dal Riada and Pictland.
Rise to power
From 623 to 624, Edwin defended Bebbanburg from an attack by King Fiachnae mac Baetain of Ulaid in response to Edwin's western expansion, as both nations desired the Isle of Man. In 626, Edwin expelled King Ceretic from Elmet, and he married the sister of King Eadbald of Kent to form a strong alliance. That same year, he survived an assassination attempt by Cwichelm of Wessex, causing him to promise Paulinus of York that he would convert to Christianity if his campaign against Cwichelm was successful. It was, and his daughter Eanfled was baptized as a result. Edwin came to engage in annual wars with his neighbors to obtain tribute, submission, and slaves, extending his kingdom from the Humber and Mersey north to the border with Scotland. He built a royal palace at Yeavering, and, on 12 April 627, Edwin himself was baptized by Frankish missionaries sent by Pope Boniface V.
From 627 onwards, Edwin ruled over Bernicia, Deira, eastern Mercia, the Isle of Man, and Anglesey. He became the Bretwalda, the overlord of the Anglo-Saxons, and he defeated his foster brother Cadwallon ap Cadfan in 629. From 632 to 633, King Penda of Mercia and Cadwallon rose against Edwin, resulting in the Battle of Hatfield Chase. Edwin was defeated and killed, and his body was hidden in Sherwood Forest at a place which came to be known as Edwinstowe ("Edwin's resting place"). His head was eventually buried at York and his body at Whitby, and he became an Orthodox, Catholic, and Anglican saint after his death.