What is the importance of Northumbria in the nonfiction book, The Age of Bede?

The kingdom of Angles in northeast England and the south of Scotland, established in 653 and conquered in 954. During that time, Northumbrian families produced many of the monks in The Age of Bede, including Benedict Biscop, Bede, Eosterwine, Ceolfrith, and Cuthbert.