Osfrith was the eldest son of Eadwine of Deira and Cwenburh, daughter of Ceorl of Mercia is today’s Person of the Week. He was born while Eadwine was in exile running from Æthelfrith of Bernicia. He returned to Deira with his father in c. 616.
Osfrith was baptized with King Eadwine on 12 April 627 in the hastily built chapel of York by Bishop Paulinus with the rest of his extended family. Before 633, Osfrith was married and had a son named Yffe. His son Yffe was born sometime between 627 and 633. He was baptized by Bishop Paulinus as an infant (but not with the rest of the family in 627).
Osfrith took part in Eadwine’s battles against King Cadwallon of Gwynedd. He was slain before his father in the battle of Hatfield Chase on 12 October 633.
After his death, Osfrith’s family fled to Kent with his stepmother Queen Æthelburgh, his minor siblings, and Bishop Paulinus. His stepmother Æthelburgh arranged for his son Yffe to be sent with her son young Uscfrea into fosterage with her cousin King Dagobert I of Austrasia, Neustria and Burgundy out of fear of her brother King Eadbald of Kent and King Oswald of Bernicia/Northumbria. Both boys died in childhood and were buried in a Frankish church.
Bede, Ecclesiastical History of the English People, Book II Chapters 14 & 20.