|Osbeorn (Osbjorn, Osbert)|
Scotland (north of the Firth of Forth)
Osbeorn (died c. 1054), given the nickname Bulax, was the son of Siward, Earl of Northumbria (died 1055). He is one of two known sons — probably the older — of Siward. While it is normally assumed he was the son of Siward's Bamburgh wife Ælfflæd, it has been suggested by William Kapelle that Osbeorn's mother was not Ælfflæd. The nickname "Bulax" probably represents the Old Norse term for "Poleaxe".
According to the most reliable sources, he died at the Battle of the Seven Sleepers, fought somewhere in Scotland between Siward and Mac Bethad mac Findlaích, King of the Scots, in 1054. Under this year, the Anglo-Saxon Chronicle, recension D, related that:
"At this time earl Siward went with a great army into Scotland, with both fleet and a land-force; and fought against the Scots, and put to flight the king Mac Bethad, and slew all that were best in the land, and brought thence much war-spoil, such as no man obtained before; And there were slain his son Osbeorn, and his sister's son Siward, and some of his housecarls, and also of the king's, on the day of the Seven Sleepers (July 27)." 
This battle was fought somewhere in Scotland north of the Firth of Forth, and is known variously as the "Battle of the Seven Sleepers" or the "Battle of Dunsinane". The location Dunsinane is not accepted as historical by modern historians, resting as it does on later medieval accounts. The earliest mention of Dunsinane as the location of the battle being the early 15th-century account by Andrew of Wyntoun.
Henry of Huntingdon related that Osbeorn had been sent to Scotland ahead of Siward:
"[Siward] sent his son to acquire Scotland. And when they reported to his father that he had been slain in battle, [Siward] said, 'Did he receive the mortal wound in front of his body, or behind?' The messengers said. 'In front'. And he replied: 'I rejoice wholly, for I would deem myself or my son worthy of no meaner death'. Siward therefore marched into Scotland and conquered the king battle ... "
Another legendary account, in the Vita et Passio Waldevi, a hagiography of Osbeorn's brother Waltheof, claimed that Osbeorn, called "Osbert Bulax", was killed by Northumbrians while his father was absent in Scotland. The accounts in Henry of Huntingdon and the Vita et Passio Waldevi are thought to be derived from a saga devoted to the life of Earl Siward.
Osbeorn's death left Siward's legacy in danger. When he died the following year, his only son Waltheof was underage and thus did not succeed immediately to the whole territory ruled by Siward, Northumbria going instead to Tostig Godwinson.
- Kapelle, Norman Conquest, p. 30
- Aird, "Siward"
- Kapelle, Norman Conquest, p. 245, n. 8
- Reany and Wilson, A Dictionary of English Surnames, p. 351
- ASC MS D, s.a. 1054; translation based on Anderson, Scottish Annals, pp. 85–6
- Aitchison, Macbeth, p. 90
- Aitchison, Macbeth, p. 90; Duncan, Kingship, pp. 35–6; see Aitchison, Macbeth, pp. 172–3, for a discussion of the possibility that Dunsinane was the location
- Darlington, McGurk and Bray (eds.), Chronicle of John of Worcester, vol. ii, pp. 574, 575, n. 15
- Translation and notes in, Anderson, Scottish Annals, p. 85
- Anderson, Early Sources, vol. i, p. 594, n. 3 (from p. 593); Michel, Chroniques Anglo-Normandes, vol. iii, p. 110
- Wright, Cultivation of Saga, pp. 75, 76, 127–33, 136
- Kapelle, Norman Conquest, p. 250, n. 66
- Kapelle, Norman Conquest, pp. 49, 87
- The Anglo-Saxon Chronicle: An edition with TEI P4 markup, expressed in XML and translated to XHTML1.1 using XSL, Tony Jebson, 2007, retrieved 2009-03-18
- Aitchison, Nick (1999), Macbeth: Man and Myth, Stroud: Sutton Publishing, ISBN 0-7509-1891-8
- Anderson, Alan Orr, ed. (1922), Early Sources of Scottish History A.D. 500 to 1286 (2 vols), Edinburgh: Oliver and Boyd
- Aird, William M. (2004), "Siward, earl of Northumbria (d. 1055), magnate", Oxford Dictionary of National Biography, retrieved 2008-03-18
- Anderson, Alan Orr, ed. (1908), Scottish Annals from English Chroniclers A.D. 500 to 1286 (1991 revised & corrected ed.), Stamford: Paul Watkins, ISBN 1-871615-45-3
- Darlington, R. R.; McGurk, P.; Bray, Jennifer, eds. (1995), The Chronicle of John of Worcester. Volume II, The Annals from 450 To 1066, Oxford Medieval Texts, Oxford: Clarendon Press, ISBN 0-19-822261-0
- Duncan, A. A. M. (2002), The Kingship of the Scots 842–1292: Succession and Independence, Edinburgh: Edinburgh University Press, ISBN 0-7486-1626-8
- Kapelle, William E. (1979), The Norman Conquest of the North: The Region and Its Transformation, 1000–1135, London: Croom Helm Ltd, ISBN 0-7099-0040-6
- Michel, Francisque, ed. (1836), Chroniques Anglo-Normandes: recueil d'extraits et d'écrits relatifs à l'histoire de Normandie et d'Angleterre pendant les XIe et XIIe siècles, II, Rouen
- Reaney, Percy Hide; Wilson, Richard Middlewood (1991), A Dictionary of English Surnames, London: Routledge, ISBN 0-415-05737-X
- Wright, C. E. (1939), The Cultivation of Saga in Anglo-Saxon England, Edinburgh: Oliver and Boyd