Ingwær (also referred to as Ingvar, Ivar or Ivarr; Old Norse: Ívarr)^{[nb 1]} was a Norse King of Northumbria. According to Æthelweard's Chronicon he was a co-king of Northumbria along with his brothers Eowils and Halfdan, though the Anglo-Saxon Chronicle does not mention him. By Æthelweard's account he died at the Battle of Tettenhall alongside his brothers in 910.

Following the Viking victory at the Battle of the Holme in 902 and the defeat of Æthelwold's Revolt the three brothers Eowils, Halfdan, and Ingwaer were among the claimants to Viking Northumbria, and were able to successfully establish their rule. The population of the Danelaw was boosted in 902 by the arrival of the Vikings of Dublin who were ejected from the city that year. Throughout the first decade of the tenth century the Viking kings of Northumbria, and the Viking king of East Anglia, carried out raids on Anglo-Saxon lands to test the resolve of Edward the Elder, the new king of Wessex. In 910 the three co-kings marched an army south and attacked Wessex. They were driven back by the Anglo-Saxons, and were pursued until Edward's forces caught up with them at Tettenhall on the fifth of August. In the ensuing battle Eowils, Halfdan and Ingwær were killed.^[2]

The identity of Ingwær and his brothers, and the nature of their rule, is subject to some debate. No coins bearing their names are known and it is possible they each ruled different parts of Northumbria, or even that they were simply commanders in the Viking army rather than kings, and their identification as such by contemporary sources is erroneous.^[3] Ingwær is known to history through Æthelweard's Latin version of the Anglo-Saxon Chronicle; in the extant Old English manuscripts he does not appear, only his brothers Eowils and Halfdan.^[1] The names of the three brothers are equivalent to the names of Ímar, Auisle, and Halfdan Ragnarsson, three Vikings active in the British Isles in the ninth century who may have been brothers. David Dumville has suggested this similarity could indicate Ingwær, Eowils and Halfdan are from the same family as the earlier trio, the Uí Ímair.^[4] According to Clare Downham, "the coincidence is perhaps too striking to be ignored".^[1]

• Downham, Clare (2007). Viking Kings of Britain and Ireland: The Dynasty of Ívarr to A.D. 1014. Edinburgh: Dunedin Academic Press. ISBN 978-1-903765-89-0.
• Dumville, David N. (2004). "Old Dubliners and New Dubliners in Ireland and Britain: a Viking-Age Story". Medieval Dublin. 6: 78–93.
• Higham, N. J.; Hill, D. H. (11 October 2013). Edward the Elder: 899–924. Taylor & Francis. ISBN 978-1-136-34948-5.
• Logan, F. Donald (2005). The Vikings in History. Taylor & Francis. ISBN 978-0-415-32756-5.
• Rollason, David (25 September 2003). Northumbria, 500–1100: Creation and Destruction of a Kingdom. Cambridge University Press. ISBN 978-0-521-81335-8.

• Inwær 1 at Prosopography of Anglo-Saxon England