Aggersborg is one of the most important archaeological monuments of Denmark's Viking Age, and the largest fortress in the Viking world. Excavations by the Danish National Museum between 1945 and 1952 revealed the largest of a series of at least five unique circular fortresses, built to a precise geometrical pattern by the [politically ambitious and] powerful king Harald Bluetooth. Below it were uncovered the rich remains of a rural settlement, founded c. 800, which in the 970s was razed to make way for the royal fortress. This monograph is the culmination of a study and interpretation of what was found at Aggersborg. Analysis of the remains of the early settlement provides a new and detailed view of the buildings, material culture and social structure of a Danish rural community in the early Viking Age. The excavation of the later fortress has shed much new light on a nodal period of Danish history in which the fortress played a crucial role. It has also resulted in important new insights into Harald's royal pretensions and his political and economic achievements, in relation both to Denmark and to the neighbouring countries of Europe. The book is edited by Else Roesdahl and Sen SindbAek of Aarhus University, together with Anne Pedersen of the National Museum of Denmark and David M. Wilson, former Director of the British Museum (who also translated this slightly abbreviated English version of the Danish monograph).