Halfdan Ragnarsson

Halfdan Ragnarsson
King of Northumbria
Reign	876–877
Predecessor	Ricsige
Successor	Guthfrith
King of Dublin
Reign	875–877
Predecessor	Eystein Olafsson
Successor	Bárid
Co-ruler of Denmark (possibly Jutland)
Reign	871–877
Predecessor	Bagsecg
Successor	Sigurd Snake-in-the-Eye
Died	877 Strangford Lough
Father	possibly Ragnar Lodbrok, or whoever was historical basis for the possibly legendary character
Mother	possibly Aslaug, or historical basis for a legendary character

Halfdan Ragnarsson (Old Norse: Hálfdan; Old English: Halfdene or Healfdene; Old Irish: Albann; died 877) was a Viking leader and a commander of the Great Heathen Army which invaded the Anglo-Saxon kingdoms of England starting in 865.

Halfdan was one of six sons of Ragnar Lodbrok named in Norse sagas; his brothers and half-brothers included Björn Ironside, Ivar the Boneless, Sigurd Snake-in-the-Eye, Ubba and Hvitserk. Because Halfdan is not mentioned in any source that mentions Hvitserk, some scholars have suggested that they are the same individual – a possibility reinforced by the fact that Halfdan was a relatively common name among Vikings and Hvitserk "white shirt" may have been an epithet or nickname that distinguished Halfdan from other men by the same name.^[1]

Halfdan was the first Viking King of Northumbria and a pretender to the throne of the Kingdom of Dublin. It is also possible he was for a time co-ruler of Denmark with his brother Sigurd Snake-in-the-eye, because Frankish sources mention a certain Sigfred and Halfdan as rulers in 873. He died at the Battle of Strangford Lough in 877 trying to press his Irish claim.