OSBERHT, OSBRITH, or OSBYRHT (d. 867), under-king of Northumbria, was of the ancient royal house of that kingdom, and was reigning before 854 (Monumenta Historica Britannica, p. 675, note c). According to the story in the ‘English Chronicle,’ his subjects deposed him in 866, and took as their king Ælla (d. 867) [q. v.] During the dissensions the Danish host crossed the Humber from East Anglia, and the rivals then united to resist them. They attacked the Danes at York, and in the issue the Northumbrians were defeated and both the kings slain. Asser relates that when Osberht and Ælla approached York, the Danes took refuge within the city. The Christians forced their way in; and the Danes, turning on them in despair, defeated them and slew both the kings. This account is reproduced by other writers, as Ethelwerd, Florence, Henry of Huntingdon, and Simeon of Durham, without substantial variation. Gaimar, however, first relates that Osberht had seduced by violence the wife of Beorn the Bute carl or merchant of York, and that his subjects consequently rebelled against him; while Beorn went to Denmark and called in the Danes to revenge him. There are several variations of this legend: one story makes Beorn bring in the sons of Ragnar Lodbrog, and another, Guthrum; while, according to one version, it was not Osberht but Ælla who seduced Beorn's wife.
[The chief authorities are contained in the Monumenta Historica Britannica, see especially pp. 795–8; Green's Conquest of England, p. 92; Freeman's Old English History, pp. 108–9.]