The purpose of this project is to understand long-term monetary development and monetisation in the Baltic Sea region during the early modern period. Using the Swedish Baltic Empire as an example, this project examines the issuance, use, and circulation of money as core elements of empire- and state-building. It also explores how the state’s monetary policies both shaped and were shaped by the practices, interests, and political participation of local powerholders and ordinary subjects. The project makes several important interventions in the existing scholarship: 1) The project incorporates monetary policy as an essential but hitherto insufficiently problematised aspect of early modern state formation in the Baltic Sea region. 2) The long-term monetary and economic development of the Baltic Sea region cannot be understood through an examination of Sweden-Finland alone; instead, by applying the concept of polycentric governance, we challenge the prevailing methodological nationalism and focus on the entire region. 3) We significantly broaden the perspective of monetary history by illuminating the ordinary subjects, their perceptions of money, and everyday practices related to it.