Byzantium and the Formation of Medieval Scandinavia: The Origins of the Norwegian Military Organization under Harald Hardrada

Legal, institutional, and cultural influences during the unification and formation of Norway in the late Viking era have largely been seen as coming from the west, especially England. Military organization has been regarded as an autochthonous development resulting from the invention of the longship and local power struggles. Yet most of its characteristics were only firmly established under Harald Hardrada (r. 1046-1066), who cast off Danish dominance, eliminated local Norwegian petty rulers, and came close to re-creating Knut the Mighty’s North Sea Empire under Norwegian hegemony. His most important resource and creation was the leidang, a national ship-levy that could muster vast fleets under the king’s authority as opposed to the military followings of regional magnates. It is argued here that Harald’s military organization, strategy and tactics as evident in his campaigns to establish his rule in Norway, his wars against Denmark and the invasion of England were profoundly influenced by his nearly decade-long career in Byzantium. Harald is set in the context of a near constant stream of Scandinavian volunteers to serve in the Byzantine army in the same period. Harald and his men provided the know-how to establish an effective, nation-wide system of corvée labor and military service geared towards building, equipping and manning large fleets that far outstripped the patchwork of magnate and royal followings typical of the Viking Age. In the process, they also created a distinction between centralized full-time forces and regional levies that could handle defense as well as support major expeditions. Finally, Harald employed strategy and tactics that evoke Byzantine military theory and practice of the late 10th and early 11th centuries. Despite his demise, the leidang remained a cornerstone of the high and late medieval Norwegian kingdom and influenced similar developments in Sweden and Denmark.