List of monarchs of Northumbria
Northumbria, a kingdom of Angles, in what is now northern England and south-east Scotland, was initially divided into two kingdoms: Bernicia and Deira. The two were first united by King Æthelfrith around the year 604, and except for occasional periods of division over the subsequent century, they remained so.
Source: Wikipedia — List of monarchs of Northumbria (CC BY-SA 4.0)