HIGHNESS, literally the quality of being lofty or high, a term used, as are so many abstractions, as a title of dignity and honour, to signify exalted rank or station. These abstractions arose in great profusion in the Roman empire, both of the East and West, and " highness " is to be directly traced to the altitudo and celsitudo of the Latin and the v^ijXorTjj of the Greek emperors. Like other " exorbitant and swelling attributes " of the time, they were conferred on ruling princes generally. In the early middle ages such titles, couched in the second or third person, were " uncertain and much more arbitrary (according to the fancies of secretaries) than in the later times " (Selden, Titles of Honour, pt. i. ch. vii. 100). In English usage, " Highness " alternates with " Grace " and " Majesty," as the honorific title of the king and queen until the time of James I. Thus in documents relating to the reign of Henry VIII. all three titles are used indiscriminately; an example is the king's judgment against Dr Edward Crome (d. 1562), quoted, from the lord chamberlain's books, ser. i, p. 791, in Trans. Roy. Hist. Soc. N.S. xix. 299, where article 15 begins with " Also the Kinges Highness " hath ordered, 16 with " Kinges Majestic," 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 title. It may be noted that Cromwell, as lord protector, and his wife were styled " Highness." In present usage the following members of the British Royal Family are addressed as " Royal Highness" (H.R.H.): all sons and daughters, brothers and sisters, uncles and aunts of the reigning sovereign, grandsons and granddaughters if children of sons, and also great grandchildren (decree of 31st of May 1898) if children of an eldest son of any prince of Wales. Nephews, nieces and cousins and grandchildren, offspring of daughters, are styled " Highness " only. A change of sovereign does not entail the forfeiture of the title " Royal Highness," once acquired, though the father of the bearer has become a nephew and not a grandson of the sovereign. The principal feudatory princes of the Indian empire are also styled " Highness."
As a general rule the members of the blood royal of an Imperial or Royal house are addressed as " Imperial " or " Royal Highness " (Altesse Impiriale, Royale, Kaiserliche, KoniglicheHoheit) respectively. In Germany the reigning heads of the Grand Duchies bear the title of Royal or Grand Ducal Highness (Konigliche or Gross-Herzogliche Hohe.it), while the members of the family are addressed as Hoheit, Highness, simply. Hoheit is borne by the reigning dukes and the princes and princesses of their families. The title " Serene Highness " has also an antiquity equal to that of " highness," for ya.\T)vbn]$ and T7juepor7js were titles borne by the Byzantine rulers, and serenitas and serenissimus by the emperors Honorius and Arcadius. The doge of Venice was also styled Serenissimus. Selden (op. cit. pt. ii. ch. x. 739) calls this title " 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 Serenissime) 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 court at Pumpernickel very accurately gives the meaning. The title of Durchlaucht was granted in 1375 by the emperor Charles IV. to the electoral princes ( Kurfiirsten). In the 17th century it became the general title borne by the heads of the reigning princely states of the empire (reichstiindische Fursten), as Erlaucht by those of the country houses (reichstiindische Grafen). In 1825 the German Diet agreed to grant the title Durchlaucht to the heads of the mediatized princely houses whether 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 prince (Furst) in the secondary meaning of that title (see PRINCE) are also styled Durchlaucht. In 1829 the title of Erlaucht, which had formerly been borne by the reigning counts of the empire, was similarly granted to the mediatized countly families (see Almanack de Golha, 1909, 107).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)