Dictionary of National Biography, 1885-1900/Osbald
OSBALD (d. 799), king of Northumbria, was, before his accession, one of the chief of the Northumbrian nobles, and was probably a member of the royal house. In December 779 he joined another ealdorman named Æthelheard in attacking Beam, son of Ælfwold, who had been made king the year before on the expulsion of King Æthelred. The two ealdormen are said to have burned Beam, setting fire, no doubt, to his house or fortress at Seletune (probably Silton, in the North Riding of Yorkshire). Alcuin, writing to King /Ethelred after his restoration in 793, addressed Osbald 'patricius,' and another ealdorman along with the king, the three being exhorted to good living. When Æthelred was murdered on 20 April 796, some of the nobles made Osbald king. After a reign of only twenty-seven days he was deserted by all the royal following and the nobles. He therefore fled the kingdom and was outlawed. He took refuge in Lindisfame, and while there probably received the letter sent him by Alcuin, reminding him that for the last two years the writer had urged him to fulfil his intention of abandoning the world and devoting himself to God, and praying him not to attempt anything on his own behalf, or add sin to sin by devastating the country. Osbald obeyed these exhortations, and sailed from Lindisfarne with a company of the brethren of the convent to the land of the Picts, became an abbot, died in 799, and was buried in the church of York.
[Sym. Dunelm. ii. 47, 57, 62 (Rolls Ser.); Flor. Wig. i. 270 (Engl. Hist. Soc.); Jaffé's Mon. Alcuin. pp. 185, 305.]