Dictionary of National Biography, 1885-1900/Ælla (d.867)
ÆLLA (d. 867), though not of royal blood, was chosen king by the Northumbrians, when they deposed Osberht. While Northumbria was divided between the parties of the two kings, the Danish host, which had wintered in East Anglia, crossed the mouth of the Humber and took York. By the intervention of the chief men of the land peace was made between the rival kings. They joined their forces, and drove the Danes into York. Part of their army succeeded in entering the city. But the Danes rallied, and after a fierce battle the Northumbrians were defeated with great slaughter. Both Ælla and Osberht were slain. This victory established the Danish power in Northumbria. This is all that is really known of Ælla. Different stories are told of him and of the cause of the Danish invasion. It is said that he caused the sea-king, Ragnar Lodbrog, to be bitten to death by serpents; that the sons of the hero came to avenge their father's death; that they took Ælla alive, and slew him in the barbarous manner described as carving an eagle on him. Another story makes Ælla violate the wife of a rich merchant of York, who avenged the wrong by calling in the invaders. This story may be compared with many others which attribute successful invasions to vengeance taken for personal wrong, and especially with the famous story of Count Julian.
[Anglo-Saxon Chron.; Asser, de rebus gestis Ælfredi; Simeon of Durham; Henry of Huntingdon, lib. v.; Saxo Gramm. ix. 176, 177; Peter Olafsson, in Langebek, Scriptores Rer. Dan. i. 111; Gaimar, 2598–2830; Mon. Hist. Brit. pp. 795–798.]