It also underlines the legitimacy and unique position of Birka and Hovgården during the Viking Age. Criterion (iii): The Birka and Hovgården complex bears exceptionally well preserved testimony to the wide-ranging trade network established by the Vikings during the two centuries of their phenomenal economic and political expansion. IntegrityWithin the boundaries of the 226 ha serial property are located all the elements necessary to express the Outstanding Universal Value of Birka and Hovgården. AuthenticityThe archaeological site of Birka and Hovgården is entirely authentic in terms of locations and settings, forms and designs, and materials and substances. Protection and management requirementsBirka and Hovgården and its buffer zone are formally protected under the Historic Environment Act (1988:950), regulations, and municipal planning instruments.