Ivar Boneless was according to the saga of Ragnar Lodbrok, the eldest son of Ragnar and Kraka. He had only cartiledge in his legs and so he could not walk, but had to be carried on a shield. However, he was fair, big, strong and one of the wisest men who have ever lived. He was consequently always the advisor of his brothers Björn Ironside, Sigurd Snake-Eye and Hvitserk.
When king Ella of Northumberland had murdered their father, Ivar's brothers tried to avenge their father, but were beaten. Ivar then went to king Ella and said that he sought reconciliation. He only asked for as much land as he could cover with an ox's hide and swore never to wage war against Ella. Then Ivar cut the ox's hide into so fine strands that he could envelope a large fortress (in an older saga it was York and according to a younger saga it was London) which he could take as his own. As he was the most generous of men, he attracted a great many warriors, whom he consequently kept from king Ella when this king was attacked by Ivar's brothers for the second time.
King Ella was captured and when the brothers were to decide how to give king Ella his just punishment, Ivar suggested that they cut "blood red eagle". This meant that Ellas back was cut open and his lungs removed. After justice had been served, Ivar became the king of England.
Ivar has lived in real life and was the son of Ragnar Lodbrok. In 855, he attacked Shippey on the Thames with his brothers Halfdan and Ubbe, in 867 he conquered York from king Ella and in 870 he killed king Edmund of East Anglia. He died in 871.