Alhfrith was King of Deira under his father, who was King of Bernicia following the death of which brother in 642?
Alhfrith: Alhfrith or Ealhfrith (c. 630 – c. 664) was King of Deira under his father Oswiu, King of Bernicia, from 655 until sometime after 664. Oswiu:  One of the sons of Æthelfrith of Bernicia, he became king following the death of his brother Oswald in 642.
i don't know