Imperial and Royal Highness
Imperial and Royal Highness (in German:Kaiserliche und königliche Hoheit) is a style possessed by someone who either through birth or marriage holds two individual styles, Imperial Highness and Royal Highness.
The style is used by members of the Habsburg dynasty who use the titles Prince Imperial and Archduke of Austria and Prince Royal of Bohemia and Hungary. One contemporary example of this is Prince Lorenz, Archduke of Austria-Este and his children who are members of the Belgian, Hungarian, and Bohemian Royal Families and of the Austrian Imperial Family at the same time.
The style was also used by the eldest son of the German Emperor who was Crown Prince of the German Empire and Crown Prince of Prussia, and also by his wife who was crown princess. It may be used for the head of the House of Hohenzollern, however this is not done anymore.
Grand Duchess Elena Vladimirovna of Russia, upon her marriage to Prince Nicholas of Greece, was styled Her Imperial and Royal Highness. Her aunt, Grand Duchess Maria Alexandrovna of Russia was alternately styled Her Imperial and Royal Highness and Her Royal and Imperial Highness upon her marriage to Prince Alfred, Duke of Edinburgh, the second son of Queen Victoria.
Due to the creation of the title of Prince of Orleans-Braganza, in 1908, members of the Brazilian Imperial Family who descend by the male line from D. Gaston, comte d'Eu and D. Isabella, Chief of the Imperial House of Brazil, are styled, by the monarchists, Imperial and Royal Highness, appart from the chief of the Imperial House, who loses the prerogative for the French throne.