The project examines the role of iron in the process during the Middle Ages - here delimited to 1150-1350 - when a Swedish kingdom was formed with a central royal power that gained control over the country. The church and the fiefdom developed into state-supporting institutions, new towns were founded and a bourgeoisie was established. The project has so far been able to point to the almost sensational fact that ore mining in Bergslagen was already taking place in the mid-9th century. There is therefore reason to believe that the revolutionary blast furnace technology was not transferred from the continent to Sweden, but may instead have originated in Scandinavia. The second phase of the project will therefore focus on comparative studies of developments in the Nordic countries and on the continent. The project's strong interdisciplinary focus and methodological approach will provide new opportunities to shed new light on the roots of the Swedish blast furnace. Iron processing became more important in the national economy, new towns were privileged, credit systems and other institutions for trade were established. The changes are thus linked to the modernization process that began during the period and which had a major impact on the formation of the state and also changed the conditions for the emergence of political power in our country. Mining was incorporated into this process through special legislation in the form of privileges issued by the new royal power.