Northumbria, the most northern of the ancient English kingdoms, stretching from the Humber northwards to the Firth of Forth, and separated westwards from Cumbria and Strathclyde by the Pennine range and the Ettrick Forest. Bernicia, the district north of the Tees, had for its first king Ida (547-559), who built Bamburgh as his capital. His grandson, Ethelfrith, mounted the throne in 593, and having married the daughter of Ella, who in 560 had formed the kingdom of Deira out of the district between the Tees and the Humber, set aside the rights of his boy brother-in-law Edwin, and so united both Bernicia and Deira into one kingdom. But the ousted Edwin, returning to defeat and slay the usurper in 617, thereupon himself became king of the Northumbrians as well as Bretwalda. Under him Northumbria was Christianised. In 633 he fell in battle against Penda of Mercia and the Welsh Cadwallon, but a year later St Oswald, son of Ethelfrith, cleared the country of the invaders, and united both divisions under his rule. His brother and successor, Oswy, was forced to yield Deira to Oswin, son of Osric, his cousin, but in 654, by a great victory in which Penda perished, was able anew to unite his kingdom, and reigned till 670 the most powerful of all Northumbrian kings. Under later kings—Egfrid (670-685), Aldfrid (685-705), a great patron of learning, and as many as fourteen obscure successors, most of whom came to a violent end—
Northumbrian influence gave way before the rise of Mercia, internal tumults, and Danish ravages, until 806, when the chroniclers cease to give a regular succession of kings, and 827, when at length Northumbria became tributary to Egbert. See the Histories of Green, Skene, and Freeman.