This book explores the international ambitions and foreign policies pursued by German monarchs relegated to 'semi-sovereign' status after 1871. When the German Reich was founded, two dozen German kings, grand dukes, dukes, and princes, formerly independent rulers, saw their realms become integrated into a federal state. At the helm of this polity stood a German Emperor. On the other hand, the Reich was a federation; by law, its twenty-five constituent states retained their sovereignty in internal matters and, to a certain extent, foreign affairs.

The book argues that both, individually and collectively, these 'semi-sovereign' monarchs helped stabilize relations between European powers for almost half a century. During the decades before the First World War, decision-makers in Europe and beyond regarded these rulers as a diplomatic wildcard, jokers in the diplomats' deck that could be played when other cards were unavailable. This study also investigates the uniqueness of these monarchs and states compared to other semi-sovereign entities in the Age of Empire.

David Korsuize is a Lecturer in the History of International Relations, Utrecht University, The Netherlands.