Until the early 19th Century, each European nation had its own system of diplomatic rank. The relative ranks of diplomats from different nations had been a source of considerable dispute, made more so by the insistence of major nations to have their diplomats ranked higher than those of minor nations.

In an attempt to resolve the problem, the Congress of Vienna of 1815 formally established an international system of diplomatic ranks. The four ranks within the system were:

1. Ambassador Extraordinary and Plenipotentiary, or simply Ambassador. A diplomatic mission headed by an ambassador would be known as an Embassy.

2. Envoy Extraordinary and Minister Plenipotentiary, or simply Envoy. A diplomatic mission headed by an envoy would be called a Legation.

3. Minister Resident, or simply Minister. A diplomatic mission headed by a minister resident would also be called a Legation.

4. Chargé d'affaires, or simply Chargé. As the French title suggests, a chargé d'affaires would be in charge of an embassy's or a legation's affairs in the (usually temporary) absence of a more senior diplomat.

Of the four diplomatic ranks, only the ambassador represents the head of state (rather than the government as is the case for the other ranks); originally only the ambassador was entitled to use the honorary title "His/Her Excellency".

As it turned out, this system of diplomatic rank did nothing to solve the problem of the nations' precedence. The appropriate diplomatic ranks used would be determined by the precedence among the nations; thus the exchanges of ambassadors (the highest diplomatic rank) would be reserved among major nations. In contrast, a major nation would probably send just an envoy to a minor nation, who in return would send an envoy to the major nation. As a result, the United States did not use the rank of ambassador until the end of the 19th Century.

By the end of World War II, it was no longer considered acceptable to treat some nations as inferior to others. Consequently the use of the ranks of envoy and minister resident gradually ceased, and for all intents and purposes the only permanent diplomatic rank used today is that of the ambassador.

See also

• Diplomacy
• High Commissioner
• Nuncio
• Windsor uniform