Alhred King of Northumbria was born to Oswulf King of Northumbria. Somewhat speculative based on the Anglo-Saxon Chronicle.
Before 774 Alhred King of Northumbria and Osgifu of Northumbria were married. He the son of Oswulf King of Northumbria.
Anglo-Saxon Chronicle. 774. This year the Northumbrians banished their king, Alred, from York at Easter-tide; and chose Ethelred (age 12), the son of Mull, for their lord, who reigned four winters. This year also appeared in the heavens a red crucifix, after sunset; the Mercians and the men of Kent fought at Otford; and wonderful serpents were seen in the land of the South-Saxons.
[his son] Osred King of Northumbria was born to Alhred King of Northumbria.
Paternal Family Tree: Bernicia