Kaiserliche und königliche Hoheit

Imperial and Royal Highness (abbreviation HI&RH) is a style possessed by someone who either through birth or marriage holds two individual styles, Imperial Highness and Royal Highness. His/Her Imperial Highness is a style used by members of an imperial family to denote imperial – as opposed to royal – status to show that the holder is descended from an Emperor rather than a King. Holders of the style Imperial Highness generally rank above holders of the style Royal Highness

A primary example of the contemporary usage of this style is the Belgian Royal Family. HI&RH Lorenz, Archduke of Austria-Este, Prince of Belgium is a member of the Imperial House of Habsburg-Lorraine by birth, but upon his marriage to HRH Princess Astrid of Belgium, he also became a member of the Belgian Royal Family by marriage. As such, their children currently use the styles HI&RH as members of both the Royal family of Belgium and the Imperial House of Habsburg-Lorraine.

In 1909, the members of the Orléans-Braganza Branch of the former Brazilian Imperial Family signed an agreement with Prince Philippe, Duke of Orléans (1869–1926), the Head of the House of Orléans (the former Royal Family of France), called the "family pact". By this agreement, all of them were counted in the French line of succession, being properly styled "Royal Highness". Combined with the earlier style "Imperial Highness", determined in the Imperial Constitution of 1824, since then on the Head of the family (named Head of the Imperial House), the Heir to the Headship (named Prince Imperial), and the eldest son of the Imperial Prince (Prince of Grão-Pará) uses the style "Imperial and Royal Highness". Other princes/princesses of the Orléans-Braganza branch (Prince/Princess of Orléans-Braganza) uses the style Royal Highness, and the members of the Saxe-Coburg-Braganza branch (Prince/Princess of Saxe-Coburg-Braganza) kept the style Highness.

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