Diplomacy, as a science or an art or both, is as old as international society. Over time the practice of diplomacy has acquired enduring, uniform institutional features and contributed to a more rational organization of international relations.

Customary rules on interstate diplomatic relations were initially codified to some extent by the Congress of Vienna (1815), yet codification of this field became completely global only in the era of the United Nations (1945–). The rules on diplomatic and consular relations are now enshrined in emblematic multilateral acts, such as the Vienna Convention on Diplomatic Relations (1961), the Vienna Convention on Consular Relations (1963), and other related instruments which have been adopted at the universal or regional level.