The Europäische Stammtafeln further mentions several theories on their family line. The elder Harald is assumed to have succeeded his brother as King of Hedeby in 798. The book places his death in 804, "killed in battle in the Irish Sea". Their children supposedly included not only Halfdan, "third" King of Hedeby (father of Harald Klak and his siblings) but two other sons. The first identified as another Harald ("fourth" King of Hedeby) and the second as Holger. Further Sigifrid and the senior Harald are given two further siblings in Europäische Stammtafeln. The third brother is identified as Halfdan the Mild, a ruler of the Yngling dynasty depicted in the Heimskringla. Their only sister is identified with Geva, wife of Windukind. The former in way of explanation of why Windukind sought refuge among the Danes. None of the theories regarding Harald's family and lineage in ES are well supported by sources. According to the Annales Bertiniani, Harald was an uncle of Rorik of Dorestad. The Annales Xantenses mention Rorik being the brother of a "younger Harald". Several modern scholars have seen this as a contradiction and chosen to identify Rorik as an apparent fifth son of Halfdan. However, Simon Coupland in From poachers to gamekeepers: Scandinavian warlords and Carolingian kings and K. Cutler in Danish Exiles in the Carolingian Empire—the Case for Two Haralds have since argued that Rorik and the "younger Harald" were brothers, both nephews of Harald Klak. The theory has gained some acceptance since the 1990s as it would explain why Harald Klak gets a mostly positive assessment in the Frankish chronicles while Rorik's brother is depicted as a raider and enemy of the Franks. This would also mean Rudolf Haraldsson, a nephew of Rorik mentioned in the Annales Xantenses, was a son of the "younger Harald". The Civil War of 812–814 There is first mention of Harald and his siblings in the Royal Frankish Annals. The entries in 811 end by mentioning the death of Charles the Younger (4 December 811) and Charlemagne wintering in Aachen. The entries in 812 begin with mention of the situation in Denmark: "Not much later the news arrived that Hemming, king of the Danes had died. Sigifrid, the nephew of King Godofrid, and Anulo, the nephew of Heriold and of the former king, both wished to succeed him. Being unable to agree on who should be king, they raised troops,