The project studies the long history of intelligence in Sweden and the long-term importance of foreign espionage as a strategic tool in political decision-making from the 17th to the 20th century. The state of knowledge about how individual European organizations developed over centuries is still weak. The study challenges prevailing views that the first organized Swedish intelligence activities were not established until the 20th century. It shows that intelligence has been a constant factor in Swedish statecraft and that the modern organization grew out of long-established practices. The study applies a long-line methodology to identify continuity and change. Six chronological case studies from both the early modern and modern periods, ca. 1600-1900, are examined and compared. The study borrows theory from several research disciplines to study organizational structures, actors and spies, operational practices, intelligence content and geographical scope, and how the activity adapted to geopolitical, constitutional and technological changes. This pioneering study deepens our knowledge of the ancient roots of modern intelligence and sheds light on its long significance in the history of statecraft. It will be an essential contribution to Swedish intelligence history, which is also placed in a broader European context.