The conduct of official affairs between states, i.e., diplomacy in the broad sense, and international relations in the broad sense differ in several respects. From a historical point of view, European diplomacy and its practice originated in fifteenth-century Italy, when the rulers of the various city-states (Venice, Florence, Rome, Parma) opened permanent embassies in one another's courts. After the Thirty Years' War, the system of diplomatic missions became widespread throughout Europe, as did diplomatic reports, the official language of which was French for a long time (replaced by English after 1945). The history of diplomacy in this sense is the history of the formal, semi-formal, and informal relations among governments, with foreign policy as its main practical domain...
