Ironmaking in Viking Age Western Scandinavia (c. AD 750-1000): Political power, knowledge transmission, and technological change

Viking Age ironmaking in Norway has often been distinguished from previous periods through the technological changes of slag handling. Put simply, when evidence for slag tapping is discovered, it is automatically assumed that the furnace in question dates to the Viking Age or Medieval period. Despite earlier significant variation within ironmaking practices, all furnaces from the Viking Age are treated as a single uniform group. Through an in-depth study of excavated sites, this thesis shows that regional variation persisted into the Viking Age, with variation seen between how iron was made across the whole of the country. Using macroscopic, microscopic and chemical analysis of ironmaking slag from five well-dated Viking Age ironmaking sites from two core ironmaking regions in Norway, different approaches to ironmaking, technological choices and regional preferences are identified. Variation within and between regions has revealed that although all Viking Age furnaces follow a similar principle regarding size, the way furnaces are built and used varies depending on where in the country the furnace is located. The work presented here expands our understanding of Viking Age ironmaking, and shows how iron was not made using a single method throughout the period, but that at least four distinct methods were in use