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Classes of Heads of Mission

Eileen Denza

From: Diplomatic Law: Commentary on the Vienna Convention on Diplomatic Relations (3rd Edition)

Professor Eileen Denza

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From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2023. All Rights Reserved. Subscriber: null; date: 08 June 2023

Heads of state and other senior officials — Diplomatic missions — Vienna Convention on the Law of Treaties — Sovereignty — States, equality

(p. 110) Classes of Heads of Mission

Article 14 

1. Heads of mission are divided into three classes, namely:

(a)  that of ambassadors or nuncios accredited to Heads of State, and other heads of mission of equivalent rank;

(b)  that of envoys, ministers and internuncios accredited to Heads of State;

(c)  that of chargés d’affaires accredited to Ministers for Foreign Affairs.

2. Except as concerns precedence and etiquette, there shall be no differentiation between heads of mission by reason of their class.

Article 15 

The class to which the heads of their missions are to be assigned shall be agreed between States.

Articles 14 to 16 and Article 18 of the Vienna Convention are a restatement in modern terms of the rules enunciated in 1815 by the eight signatories of the Regulation of Vienna: Austria, Spain, France, Great Britain, Portugal, Prussia, Russia, and Sweden.1 The historical significance of the Regulation was that by establishing only three classes of envoy and providing that in each class precedence should be determined by the date of official notification of arrival it greatly reduced both disputes over precedence and proliferation of ranks of head of mission. Only monarchies and republics of equivalent standing were in 1815 accepted as entitled to send ambassadors—holding as of right the title of Excellency and the privilege of personal audience at any time with (p. 111) the receiving sovereign.2 Heads of mission in the second class, though also accredited to the receiving head of state, lacked these privileges and ranked below ambassadors. Proliferation of titles arose as a result of the constant struggle to secure precedence by those States which lacked either the political power or the financial resources to maintain full embassies abroad.

The title of nuncio denoted a permanent diplomatic representative of the Holy See. In 1965 the Holy See established the new rank of apostolic pro-nuncio, like the apostolic nuncio a diplomatic representative within the first class, but accredited to those States which did not confer on the representative of the Holy See the status of dean, or doyen, of the diplomatic corps. According to Cardinale, who set out the origins of the titles and functions of the Papal representatives: ‘The prefix pro precedes the name nuncio so as to insinuate the idea of substitution. In other words, the Holy See hopes some day to accredit a nuncio with de jure deanship to a given post, but in the meantime sends a pro-nuncio.’ In 1994, however, the title of pro-nuncio was placed in abeyance for the purpose of new diplomatic appointments. New appointments from 1994 onwards in all capitals were given the title of nuncio and no longer expected to enjoy automatic deanship of the diplomatic corps. The change may have been for the purpose of reducing the number of diplomatic titles, particularly since pro-nuncio was not a title recognized in the Vienna Convention.3

Internuncios were originally Papal representatives who might not be permanent, but by the time of the 1815 Vienna Regulation were permanent representatives within the second class. Apostolic delegates by contrast are not accredited to a sovereign or Minister of Foreign Affairs but to the Church and the Catholic population in a prescribed region.4

The measure of general acceptance which other States, from courtesy or convenience, accorded to the Vienna Regulation is demonstrated by the very small amount of change that was required to adapt it to modern diplomatic usage.

Article 14 paragraph 1 of the Vienna Convention replaces Article 1 of the 1815 Vienna Regulation. Only three changes were made to the text. Since the classification in the Vienna Convention is of ‘heads of mission’, it was necessary to remove from the first class the Papal legates, since these were (p. 112) invariably ad hoc emissaries in the Papal diplomatic service.5 Within the first class were added ‘and other heads of mission of equivalent rank’ in order to cover High Representatives of States in the French Communauté and High Commissioners of States within the British Commonwealth. These heads of mission are not accredited, since the sending and receiving States share the same Head of State. The additional words, in an amendment proposed by Ghana at the Vienna Conference, replaced a UK amendment which had been criticized as too specific for a general international convention.6 The second class was altered by deleting from the 1815 text the words ‘ou autres’ which had been taken to refer to ministers resident (who were in 1818 covered as a separate third class by the Protocol of Aix-la-Chapelle7), to ad hoc emissaries to heads of state, and to internuncios.8 Ministers resident, already a dwindling class in 1815, had become obsolete, and ad hoc emissaries were relegated by the Conference for separate and later treatment (in the New York Convention on Special Missions), leaving only internuncios—who were expressly added.

Reduction in the classes of head of mission

The most controversial question relating to the classes of heads of mission in the Vienna Convention was whether the process of simplification should not be carried a stage further by reducing the classes to two. This had in fact been attempted in 1927. The Committee of Experts for the Progressive Codification of International Law set up by the Council on the request of the Assembly of the League of Nations appointed a subcommittee which recommended reducing the classes of diplomatic agent to those of ambassador and of chargé d’affaires. They argued that one purpose of the classification drawn up by the Congress of Vienna was to secure for the representatives of the Great Powers, who then enjoyed the exclusive entitlement to send ambassadors, continued precedence. With the obsolescence of those privileges which constituted the ‘representative character’, all heads of mission should be styled by the same title, since they represented the same interests and performed the same functions. Authorities on diplomatic law including Pinheiro-Ferreira, Pradier-Fodéré, Suarez, and (p. 113) Fiore were quoted to that effect. The Committee of Experts therefore circulated to governments the following question:

Is it desirable to revise the classification of diplomatic agents made by the Congresses of Vienna and Aix-la-Chapelle? In the affirmative case, to what extent should the existing classes of diplomatic agents be amalgamated, and should each State be recognised to have the right, in so far as existing differences of class remain, to determine at its discretion in what class its agents are to be ranked?

Of the twenty-seven States addressed, eleven were opposed to any modification of the existing position, and since they included Great Britain and other Commonwealth countries, France, Germany, and the United States—the most powerful States and those with the longest diplomatic traditions—there was little hope of agreement on a revision. Opponents of the proposals maintained that they did not correspond to the facts of political life or to the need to preserve a hierarchical structure within the diplomatic service of each State. Belgium, supporting the opponents of change, observed that some States sought by maintaining relations at the level of ambassador to give greater significance to their relations or to emphasize close links between them.9

Over the next thirty years the trend towards appointing ambassadors accentuated. The Soviet Union in 1941 reverted to appointing ambassadors—its early egalitarian decision of 1918 to send only ‘plenipotentiary representatives’ having met with a general response of placing them in the lowest class of chargés d’affaires. When the United States and Switzerland (in 1957) began to accredit and to receive ambassadors it became clear that neither a republican constitution nor the small size of a State was any longer a bar. The United Nations was under Article 2 of its Charter based on the sovereign equality of its members, and inequality of classes of representatives appeared to be inconsistent with that principle.

In the light of these developments, the Rapporteur’s original draft for the International Law Commission again proposed reduction of the classes of head of mission to two—those of ambassador and of chargé d’affaires. While members of the Commission accepted that there were no surviving legal distinctions between ambassadors, envoys, and ministers and that the use of different grades to convey political distinctions could be seen as contrary to the principle of the sovereign equality of States, it was also pointed out that some States would face constitutional difficulties. The general reaction was that (p. 114) amalgamation might be premature and lessen the chances of a Convention being generally acceptable. Although there were few modern examples of the exchange of envoys or of ministers, the rank was selected usually to denote a certain coolness in the relations thereby established.10

At the Vienna Conference amendments were put forward by Mexico and Sweden, and by Switzerland, to acknowledge modern practice and to reduce the categories to those of ambassador and of chargé d’affaires. The reaction in the Conference was, however, that expressed by the representative of Tunisia: ‘To eliminate that class would be premature and might make it difficult for some States to become parties to the convention. It would be better to leave events to follow their natural course.’ The Conference therefore left the three categories contained in the 1815 Vienna Regulation. Paragraph 2 of Article 14, expressly limiting the significance of the different classes to precedence and etiquette, had to suffice as an expression of the legal equality between sovereign States.11

Article 15 does not imply that the heads of mission exchanged between two States must belong to the same class. As the International Law Commission commented, there are instances where that has not been the case.12

Subsequent practice

Ten years after the conclusion of the Vienna Convention, heads of mission in any class other than that of ambassador had almost disappeared. In the United States, the Bulgarian Legation was the last survivor, in Paris, Monaco and San Marino still maintained legations, while in Brussels there remained five ministers.13 In 1982 the United Kingdom upgraded its mission to the Holy See to an embassy, in the context of establishing full diplomatic relations. In a written answer to Parliament, the Minister commented: ‘The maintenance at the Holy See of our only remaining Legation was an anomaly, based on historical considerations which have long lost their significance.’14 Relations between (p. 115) the United Kingdom and China constituted another anomaly, but in 1972 in the context of a political settlement in which the United Kingdom ‘took note’ of China’s position on Taiwan they were raised from the level of chargés d’affaires to that of full ambassadors. Relations between the United Kingdom and Albania also resumed in 1991 at the level of chargé d’affaires and only in 1996 were they raised to the level of ambassadors.15 By 1990 the process appeared to be complete and in the major capitals at least all permanent heads of mission were ambassadors or of equivalent rank.16


Règlement sur le rang entre les agents diplomatiques: Satow (4th edn 1957) p 162; Genet (1931) vol I p 267; ILC Yearbook 1958 vol II pp 93–4; Salmon (1994) para 135.

On the virtual disappearance in modern times of the right of access to the receiving head of state, see Satow (5th edn 1979) para 11.11.

Noonan, Jr (1996) at pp 92–3. Thanks are due to Canon Michael Brockie, to Mgr Joseph Marino, First Counsellor in the Apostolic Nunciature in London and to Mgr Vincent Brady, Secretary to the Nunciature for information on the change of practice by the Holy See.

Cardinale (1976) pp 136–50; Satow (5th edn 1979) paras 11.12–16; Noonan, Jr (1996) 92–3.

Maulde-la Clavière (1892) pp 328–8; ILC Yearbook 1958 vol II p 9 para 1(a) of Commentary on Arts 13–16; UN Doc A/Conf. 20/14 p 119 (representative of Holy See).

UN Docs A/Conf. 20/C 1/L 11 (UK), L 177 (Ghana); A/Conf. 20/14 pp 115–20.

Protocole de la Conférence du 21 novembre 1818 instituant une nouvelle classe d’agents diplomatiques: Genet (1931) vol I p 268; Satow (4th edn 1957) p 163.

UN Doc A/CN 4/116 p 30 (comment of Rapporteur on observation of Switzerland); ILC Yearbook 1958 vol I p 118 (Mr Sandström).

Text of replies in League of Nations Publication C 196.M 170.1927. V. Analysis in Genet (1931) vol I pp 286–92; Satow (4th edn 1957) p 173; ILC Yearbook 1956 vol II pp 145–6; Hill (1927) p. 737; Salmon (1994) para 140.

10  UN Doc A/CN 4/91 Art 7 and Commentary pp 15–16; ILC Yearbook 1957 vol I pp 33–9, vol II pp 93–4.

11  UN Docs A/Conf. 20/C 1 L 57 (Mexico and Sweden) and L 108 (Switzerland); A/Conf. 20/14 pp 115–20, 14.

12  ILC Yearbook 1958 vol II p 94, para (3) of Commentary on Arts 13–16; UN Doc A/Conf. 20/14 p 115 (representative of Switzerland).

13  Salmon (1994) para 142; US v Kostadinov, USCA 2nd Cir 1133, Judgment of 10 May 1984; 99 ILR 103.

14  Hansard HC Debs 25 January 1982 WA cols 245–6; 1982 BYIL 416.

15  Satow (5th edn 1979) para 11.5; The Times, 22 February 1996.

16  Lecaros (1984) p 77; Salmon (1994) para 142; Richtsteig (1994) p 38; London Diplomatic List June 1996 pp 75–7.