Ragnar is said to have been the father of three sons—Halfdan, Inwaer (Ivar the Boneless), and Hubba (Ubbe)—who, according to the Anglo-Saxon Chronicle and other medieval sources, led a Viking invasion of East Anglia in 865. They may have sought to avenge Ragnar’s death, which may or may not have been murder, or they may have been claiming land to which they believed they had a right as a result of a previous invasion by Ragnar that may or may not have actually happened. This sort of ambiguity pervades much that is thought to be known about Ragnar, and it has its roots in the European literature created after his death.