Duke of Leuchtenberg

Duke of Leuchtenberg was a title created twice by the monarchs of Bavaria for their relatives. The first creation was awarded by Maximilian I, Elector of Bavaria to his son Maximilian Philipp Hieronymus, upon whose death without children the lands passed back to his nephew Elector Maximilian II. It was re-created by Maximilian I Joseph, King of Bavaria on 14 November 1817 and awarded to his son-in-law Eugène de Beauharnais. Eugène was the adopted stepson of the deposed Emperor Napoleon I of France, and Eugène had been his heir in Frankfurt and briefly in Italy. King Maximilian Joseph compensated his son-in-law after he lost his other titles and named him heir to the kingdom after the male-line descendants of the royal house and next in precedence after the Royal Family.

The companion title, also in the Bavarian peerage, was Prince of Eichstätt, which was resigned by the 4th Duke to the King of Bavaria in 1855. On 14 July 1839, Emperor Nicholas I of Russia granted the Russian and Finnish style Imperial Highness to the 3rd Duke, Maximilian, who had just married his daughter, Grand Duchess Maria Nikolaevna.

Nicholas, 4th Duke of Leuchtenberg, was named as Duke of Leuchtenberg in the Russian Empire in 1890 by Alexander III of Russia, as they were by then members of the extended Russian Imperial Family. This creation elevated the style from Serene to Imperial Highness, and was to be carried by all male line descendants of Nicholas born of marriages of corresponding rank, of the incumbent Duke from 1852 to 1891. The title was largely ceremonial, with no lands or governance attached; the style and title became "Duke von (or of) Leuchtenberg, de Beauharnais".

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