Napoléon, Prince Imperial, also known as Louis-Napoléon, was the only child of Napoleon III, Emperor of the French, and Empress Eugénie. After his father was dethroned in 1870, he moved to England with his family. On his father's death in January 1873, he was proclaimed by the Bonapartist faction as Napoleon IV.

Prince Napoléon Joseph Charles Paul Bonaparte, usually called Napoléon-Jérôme Bonaparte or Jérôme Bonaparte, was the second son of Jérôme, King of Westphalia, youngest brother of Napoleon I, and his second wife Catharina of Württemberg. Following the death of his nephew Louis-Napoléon, Prince Imperial in 1879, he claimed headship of the House of Bonaparte until his death in 1891. An outspoken liberal however, he was passed over as heir in his cousin's final will, instead choosing his elder son Victor, who was favored by most Bonapartists. From the 1880s he was one of the stronger supporters of General Georges Boulanger, together with other monarchist forces.