Royal Highness

Royal Highness is a style used to address or refer to some members of royal families, usually princes or princesses. Kings and their female consorts, as well as queens regnant, are usually styled Majesty. When used as a direct form of address, spoken or written, it takes the form Your Royal Highness. When used as a third-person reference, it is gender-specific (His Royal Highness or Her Royal Highness, both abbreviated HRH) and, in plural, Their Royal Highnesses (TRH). By the 17th century, all local rulers in Italy adopted the style Highness, which was once used by kings and emperors only. According to Denis Diderot's Encyclopédie, the style of Royal Highness was created on the insistence of Archduke Ferdinand of Austria, Cardinal-Infante of Spain, a younger son of King Philip III of Spain. The archduke was travelling through Italy on his way to the Low Countries and, upon meeting Victor Amadeus I, Duke of Savoy, refused to address him as Highness unless the Duke addressed him as Royal Highness. Thus, the first use of the style Royal Highness was recorded in 1633. Gaston, Duke of Orléans, younger son of King Henry IV of France, encountered the style in Brussels and assumed it himself. His children later used the style, considering it their prerogative as grandchildren of France. By the 18th century, Royal Highness had become the prevalent style for members of a continental reigning dynasty whose head bore the hereditary title of king or queen. The titles of family members of non-hereditary rulers (e.g., the Holy Roman Emperor, King of Poland, Princes of Moldavia and Wallachia—and even the kin of the Princes of Orange who held hereditary leadership though not monarchical position in much of the Netherlands, etc.) were less clear, varying until rendered moot in the 19th century. After dissolution of the Holy Roman Empire in 1806, several of Germany's prince-electors and other now sovereign rulers assumed the title of grand duke and with it, for themselves, their eldest sons and consorts, the style of Royal Highness (Baden, Hesse, Mecklenburg, Saxe-Weimar).