Ragnar Lodbrok or Lothbrok (Old Norse: Ragnarr Loðbrók, "Ragnar Hairy Breeches") was a legendary Norse ruler and hero from the Viking Age described in Old Norse poetry and several sagas. In this tradition, Ragnar was the scourge of France and England and the father of many renowned sons, including Ivar the Boneless, Björn Ironside, Halfdan Ragnarsson, Sigurd Snake-in-the-Eye, and Ubbe Ragnarsson.
Halfdan Ragnarsson was a Viking leader and a commander of the Great Heathen Army. According to the tradition recorded in the Norse sagas he was one of the sons of Ragnar Lodbrok, and his brothers included Björn Ironside, Ivar the Boneless, Sigurd Snake-in-the-Eye and Ubba. He was the first King of Jórvík and also claimed the Kingdom of Dublin. He died at the Battle of Strangford Lough in 877 trying to press his Irish claim.