The nineteenth century witnessed the transformation of the European embassy from an essentially personal representation of one sovereign to another into a complex bureaucratic institution that served as the nervous system of international politics. This transformation was neither smooth nor uniform across the continent, but it fundamentally altered how states interacted, how wars were prevented or precipitated, and how the balance of power was maintained. The story of European embassies in this period is inseparable from the broader narrative of European political history, touching on questions of war and peace, revolution and reaction, empire and nationalism, tradition and modernity.