Excellency is an honorific style given to certain high-level officers of a sovereign state, officials of an international organization, or members of an aristocracy. Once entitled to the title "Excellency", the holder usually retains the right to that courtesy throughout their lifetime, although in some cases the title is attached to a particular office and is held only during tenure of that office.
Generally people addressed as Excellency are heads of state, heads of government, governors, ambassadors, Roman Catholic bishops, high-ranking ecclesiastics and others holding equivalent rank, such as heads of international organizations. Members of royal families generally have distinct addresses such as Majesty, Highness, etc.
While not a title of office itself, the honorific Excellency precedes various titles held by the holder, both in speech and in writing. In reference to such an official, it takes the form His or Her Excellency; in direct address, Your Excellency, or, less formally, simply Excellency. The abbreviation HE is often used instead of His/Her Excellency; alternatively it may stand for His Eminence.
Government
Heads of state and government
In most republican nation states, the head of state is formally referred to as His or Her Excellency.
If a republic has a separate head of government, that official is almost always addressed as Excellency as well. If the nation is a monarchy, however, the customs may vary. For example, in the case of Australia, all ambassadors, high commissioners, state governors and the governor-general and their spouses are entitled to the use of Excellency.
Governors of colonies in the British Empire were entitled to be addressed as Excellency and this remains the position for the governors of what are now known as British Overseas Territories.
International diplomacy
In various international organizations, notably the UN and its agencies, Excellency is used as a generic form of address for all republican heads of state and heads of government. It is often granted to the organization's head as well, and to those chiefs of UN diplomatic missions, such as Resident Coordinators (who are the designated representatives of the Secretary-General), who are accredited at the Head of State level (like an Ambassador), or at the lower Head of Government level.
In recent years, some international organizations, such as the Organization for Security and Co-operation in Europe, or the European Union, have designated their permanent representatives in third countries as ambassadors, although they do not represent sovereign entities. This is now largely accepted, and because these ambassadors rank after the UN representative in the orders of precedence of representatives of international organizations, the UN coming naturally first as pre-eminent, the UN Resident Coordinators are now also commonly but informally referred to in diplomatic circles as ambassadors, although the UN itself does not refer to them in this way.
International judiciary
Judges of the International Court of Justice also enjoy the style of Excellency.
Monarchy
Royalty
In some monarchies the husbands, wives, or children of a royal prince or princess, who do not possess a princely title themselves, may be entitled to the style. For example, in Spain spouses or children of a born infante or infanta are addressed as Excellency, if not accorded a higher style.
Former members of a royal house or family, who have forfeited a royal title, may be awarded the style afterwards. Examples are former husbands or wives of a royal prince or princess, including Alexandra, Countess of Frederiksborg, following her divorce from Prince Joachim of Denmark. Likewise, Count Carl Johan Bernadotte of Wisborg, who lost his succession rights to the Swedish throne and discontinued use of his royal titles in 1946 when he married the commoner Elin Kerstin Margaretha Wijkmark, was accorded the style.
In some emirates, such as Kuwait and Qatar, the Emir, heir apparent and prime minister are called His Highness. Their children are styled with His/Her Excellency unless they possess a higher honorific.
Nobility
In Spain members of the high nobility, holding the dignity of grandee, are addressed as The Most Excellent Lord/Lady.
In Denmark, some counts (lensgrever), historically those related by blood or marriage to the Danish monarch, who have entered a morganatic marriage or otherwise left the Royal Family have the right to be styled as Your Excellency, e.g., the Counts of Danneskiold-Samsøe, some of the counts of Rosenborg and the Countess of Frederiksborg (ad personam).