Eugène Rose de Beauharnais, Duke of Leuchtenberg (3 September 1781 – 21 February 1824) was the first child and only son of Alexandre de Beauharnais and Joséphine Tascher de la Pagerie, first wife of Napoleon I.

He was born in Paris, France, and became the stepson and adopted child (but not the heir to the imperial throne) of Napoleon I. His biological father was executed during the revolutionary Reign of Terror. He commanded the Army of Italy and was Viceroy of Italy under his stepfather.

Historians have looked upon him as one of the ablest of Napoleon's relatives.

Eugène's first campaign was in the Vendée, where he fought at Quiberon. However, within a year his mother Joséphine had arranged his return to Paris. In the Italian campaigns of 1796–1797, Eugène served as aide-de-camp to his stepfather, whom he also accompanied to Egypt. In Egypt, Eugène was wounded during the Siege of Acre (1799) and returned to France with Napoleon in the autumn of 1799, helping to bring about the reconciliation of the General and his mother, who had become estranged due to the extramarital affairs of both. During the Coup of Brumaire, Eugène accompanied Napoleon to Saint-Cloud, where the legislative assemblies were brought into submission.

When Napoleon became First Consul following Brumaire, Eugène became a captain in the Chasseurs à Cheval of the Consular Guard. With his squadron took part in the Battle of Marengo where, though half his men fell, he led charge after charge.

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