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 Leuchtenberg, de Beauharnais". Following the death of the 8th Duke in 1974, no remaining heirs of full dynastic status remained; the 8th Duke's parents' marriage was the last equal marriage entered into by a male dynast of the House of Beauharnais. The title is claimed by Nicolas de Leuchtenberg, senior heir of the 4th Duke by a morganatic marriage, whose son Nicolas was titled in 1890 Duke of Leuchtenberg by edict of Tsar Alexander III of Russia.
** Nicolas Maximilianovitch, 4th Duke of Leuchtenberg, prince Romanowsky, buried in a monastery near St Petersburg. On 5 July 1868, he married Nadejda Annenkova, two children:
*** Nicolas Nicolaïevitch de Leuchtenberg, married Countess Maria Nicolaïevna Grabbe on 6 September 1894, 7 children, including:
**** Alexandra Nicolaïevna de Leuchtenberg, princess Romanowskaya, in 1916 married Prince Levan Melikov , in 1922 married Nicolas Terestchenko
**** Nicolas Nicolaïevitch de Leuchtenberg, married Olga Fomina, on 8 September 1919 at Novotcherkask and then remarried on 3 November 1928 at Munich, to Élisabeth Müller-Himmler, two children by his second marriage:
***** Eugénie Élisabeth de Leuchtenberg, in 1958 married Martin von Bruch
***** Nicolas de Leuchtenberg, on 24 August 1962 married Anne Bügge, two children:
***** Michael Alexandrovich de Beauharnais-Mogilevsky married Joan Russell
****** Michelle de Beauharnais Mogilevsky in 1980 married Jeffre Harrison
****** Anton de Beauharnais Mogilevsky in 1995 married Holly Jill Smith
****** André Jon de Beauharnais Mogilevsky married Kimberly Potter
**** Maximilien Nicolaïevitch de Leuchtenberg
**** Serge Nicolaïevitch de Leuchtenberg, in 1925 married Anne Naumova,, in 1939 married Kira Wolkova,, and finally married Olga Wickberg, two children by his third marriage:
***** Serge Sergeïevitch
***** Elizabeth Sergeïevna
*** Georges de Leuchtenberg,, prince Romanowsky, in 1895 married Princess Olga Repnina, 6 children:
**** Elena Gheorghievna
**** Dmitri Gheorghievitch, in 1921 married Ekaterina Alexeïevna Arapova, 2 children:
***** Hélène
***** Georges Dmitrievitch
**** Natalia Gheorghievna
**** Tamara Gheorghievna
**** André Gheorghievitch
**** Constantin Gheorghievitch, in 1929 married Princess Daria Alexeïevna Obolensky, 2 children:
