Highness (Latin: Celsitudo; Italian: Altezza) is an attribute referring to the rank of the dynasty in an address. It is literally the quality of being lofty or high, a term and style used, as are so many abstractions, as a style of dignity and honour, to signify exalted rank or station. As with all attributes of nobility, it is typically used with a possessive adjective: "His Highness", "Their Highnesses", etc.
 Western and European tradition
Abstract styles arose in great profusion in the Roman Empire, especially in the Byzantine continuation. Currently such styles can be subject to confusion, as their meaning was affected by inflation and devaluation, but at any given time they were rather rigidly ruled by imperial commands, rendering the official hierarchy of offices; for example at the time of the Notitia Dignitatum, the highest offices were grouped in classes, each awarded a characteristic title on top of every functional one, the highest being Illustris, next Spectabilis, et cetera. Like other exorbitant and swelling attributes of the time, the higher styles were conferred on imperial and ruling foreign princes generally as well as attached to various offices at court or in the state (military, financial, judiciary and various other, often combined, central and provincial administrations), clarifying the protocollary hierarchy (often deviating from the political reality, though).
In English usage, the terms Highness, Grace (which is not used exclusively for the sovereign), and Majesty, were all used as honorific styles of Kings and Queens until the time of James I of England. Thus in documents relating to the reign of Henry VIII of England, all three styles are used indiscriminately; an example is the King's judgment against Dr. Edward Crome (d. f562), quoted, from the Lord Chamberlains' books, ser. I, p. 791, in Trans. Roy. Hist. Soc. N.S. lOX. 299, where article 15 begins with Also the Kinges Highness hath ordered, 16 with Kinges Majestie, and 17 with Kinges Grace. In the Dedication of the Authorized Version of the Bible of 1611, James I is still styled Majesty and Highness; thus, in the first paragraph: "the appearance of Your Majesty, as of the Sun in his strength, instantly dispelled those supposed and surmised mists ... especially when we beheld the government established in Your Highness and Your hopeful Seed, by an undoubted title". It was, however, in James I's reign that Majesty became the official style. It may be noted that Oliver Cromwell and his wife were also styled "Highness" upon his elevation to Lord Protector of the Commonwealth; presidents and other republican heads of state are normally styled "Excellency".
In present usage the following members of the British Royal Family normally have the right to be addressed as Royal Highness (HRH, His or Her Royal Highness): The children of past and present Sovereigns, the grandchildren in the male-line and the eldest son of the eldest son of the Prince of Wales (decree of 31 May 1898). A change of sovereign does not entail the forfeiture of the style of Royal Highness. However, the sovereign has the right to grant or revoke the style of HRH and other titles.
As a general rule, the members of the blood royal of an Imperial or Royal house are addressed as Imperial or Royal Highness (French Altesse Imperiale, Altesse Royale; German Kaiserliche Hoheit, Königliche Hoheit; Spanish Alteza Imperial, Alteza Real, etc.) respectively.
In Germany, Austria (and other former parts of the Holy Roman Empire) the reigning heads of the Grand Duchies bear the title of Royal Highness (Königliche Hoheit), while other members of the family are simply addressed as Grand Ducal Highness or Highness (Großherzogliche Hoheit or Hoheit). Hoheit is borne by the reigning dukes and the princes and princesses of their families.
The style Serene Highness has an antiquity equal to that of highness, and was a title borne by the Byzantine rulers, as were serenitas and serenissimus by the Emperors Honorius and Arcadius. The Doge of Venice was also styled Serenissimus (Latin 'Most Serene'). The crowned republic and the city itself remain widely known as la Serenissima. Selden (op. cit. part II. ch. X. 739) calls this style one of the greatest that can be given "to any Prince that hath not the superior title of King". In modern times Serene Highness (Altesse Sérénissime) is used as the equivalent of the German Durchlaucht, a stronger form of Erlaucht, illustrious, represented in the Latin honorific superillustris- Thackeray's burlesque title Transparency in the fictitious court at Pumpernickel very accurately gives the meaning. The style of Durchlaucht was granted in 1375 by the Emperor Charles IV to the electoral princes (Kurfürsten), the highest rank under the Roman Emperor).
In the 17th century it became the general style borne by the heads of the reigning princely states of the empire (reichsständische Fürsten), as Erlaucht by those of the comital houses (reichsständische Grafen, i.e. Counts of the Empire). In 1825 the Imperial German Diet agreed to grant the style Durchlaucht to the heads of all mediatized princely houses domiciled in Germany or Austria, and it is now customary to use it of the members of those houses. Further, all those who are elevated to the rank of Fürst (prince in the *secondary meaning of that title) are also styled Durchlaucht. In 1829 the style of Erlaucht, which had formerly been borne by the reigning Counts of the empire, was similarly granted to the mediatized countly families (Almanach de Gotha, 1909, 107).
His Highness, often abbreviated HH, is a style for members of ducal families, some grand ducal families, and lesser members of some royal families. The third case is the only usage of the style that is still used officially. However, socially, many formerly-reigning ducal and grand ducal families assume the style HH, but this is only used socially and they are not normally referred to as such in any official capacity.
The style is officially used by junior members of the royal houses of Denmark and the Netherlands. Before 1917, it was also used by some junior members of the British royal house. The style was also once used by the ruling families of the Grand Duchies of Saxe-Weimar-Eisenach, Oldenburg, Mecklenburg-Schwerin, and Mecklenburg-Strelitz, and of the Duchies of Brunswick, Anhalt, Saxe-Coburg and Gotha, Saxe-Meiningen, and Saxe-Altenburg, as well as by the House of Schleswig-Holstein, which never ruled. Surviving members of these families are sometimes known by the style.
Example of official holders of the style Highness:
- His Highness Prince Maurits of Orange-Nassau, Van Vollenhoven, son of HRH Princess Margriet of the Netherlands and Mr. Pieter van Vollenhoven, the maternal grandson of HM Queen Juliana of the Netherlands, and nephew of HM Queen Beatrix. Upon his mother's marriage, it was decreed that her children would be known as HH Prince(ss) <name> of Orange-Nassau, Van Vollenhoven.
- His Highness Prince Nikolai of Denmark, son of HRH Prince Joachim of Denmark and HE Alexandra, Countess of Frederiksborg, the paternal grandson of HM Queen Margrethe II of Denmark.
- His Highness Prince Sverre Magnus of Norway son of HRH Crown Prince Haakon and HRH Crown Princess Mette-Marit of Norway, the paternal grandson of HM King Harald V of Norway.
Examples of other people entitled to the style Highness:
- His Highness Prince Andreas of Saxe-Coburg-Gotha, the current Head of the Ducal Family of Saxe-Coburg-Gotha. His actual official name is Andreas Prinz von Sachsen-Coburg und Gotha as since the fall of the monarchy the German state has not recognised royal or aristocratic titles or styles except as a part of the surname. Nonetheless, the style is still correctly used by members of formerly-reigning families. It is not regarded as appropriate that the German republican state should be an arbiter of nobiliary or royal styles and these families therefore still use these styles even though the state itself does not recognise them.
- His Highness Duke Christoph of Schleswig-Holstein, the current Head of the Ducal Family of Schleswig-Holstein. His actual official name is Christoph Herzog von Schleswig-Holstein, on the same basis as above.
- His Highness Duke Georg Borwin of Mecklenburg, the current Head of the Grand Ducal Family of Mecklenburg-Strelitz. His actual official name is Georg Borwin Herzog zu Mecklenburg, on the same basis as above.
 African usage
In most of Africa, many styles are used by traditional royalty. Generally the vast majority of the members of these royal families use the titles Prince and Princess, while the higher ranked amongst them also use either Highness or Royal Highness to describe secondary appellations in their native languages that they hold in their realms, appellations that are intended to highlight their relative proximity to their thrones, either literally in the sense of the extant kingships of the continent or symbolically in the sense of its varied chiefships of the name, and which therefore serve a function similar to the said styles of Highness and Royal Highness. For example, the Yoruba people of West Africa usually make use of the word Kabiyesi when speaking either to or about their sovereigns and other royals. As such, it is variously translated as Majesty, Royal Highness or Highness depending on the actual rank of the person in question, though a literal translation of the word would read more like this: He (or She) whose words are beyond questioning, Great Lawgiver of the Nation.
 Colonial use
- In the British Empire, the style (His) Highness became reserved for the elite of the feudatory dynastic heads of the major princely states (mainly in India and other territories—as on the Persian Gulf coast—once under the Honourable East India Company).
- In various other empires, such as the Dutch East Indies (see List of regencies and cities of Indonesia), a similar system was introduced.
 Other uses
Regardless of the official traditions in the various colonial empires, the style is evidently used to render, often merely informally, various somewhat analogous titles in non-western cultures, regardless whether there is an actual linguistic and/or historical link.
In Samoa, for example, the heads of the four paramount dynasties carry the title of His/Her Highness. Both the current and previous Heads of State are styled His Highness. Furthermore, in North America, some chiefs of certain tribes or nations use the attribute of Highness.
The present Aga Khan was granted the style of 'His Highness' by Elizabeth II, Queen of the United Kingdom in 1957 upon the death of his grandfather Aga Khan III. This has been a traditional gesture by British sovereigns since the first Aga Khan allied himself with Britain against Afghanistan
 Variations and precedence
While the actual precedence depends on the rank itself, and sometimes more specifically on the monarchy, rather than on the style of address, the holders tend to end up roughly in the following order of precedence:
- His/Her Imperial and Royal Highness (HI&RH; ranks with HIH);
- His/Her Imperial Highness (HIH; ranks with HI&RH)
- His/Her Royal Highness (HRH)
- His/Her Grand Ducal Highness (HGDH), used by junior members of the houses of Luxembourg, Grand Ducal Hesse, and Baden
- His/Her Exalted Highness (HEH), used only by the Nizam of Hyderabad, the pre-eminent Indian princely ruler
- His/Her Highness (HH)
- His/Her Sultanic Highness (HSH), a rare, hybrid western-Islamic honorific style, exclusively used by the son, daughter-in-law and daughters of Sultan Hussein Kamel of Egypt
- His/Her Ducal Serene Highness (HDSH)
- His Most Eminent Highness (HMEH), a hybrid with His Eminence, created in 1630 for the Grand Master of the Knights of Malta, as Prince of the Holy Roman Empire at par with a Cardinal (Prince of the Church).
- His/Her Most Serene Highness (HMSH)
- His/Her Serene Highness (HSH)
- His/Her Illustrious Highness (HIll.H)
 See also