The titles of Prince de la Moskowa (English: Prince of the Moskva) and Duc d'Elchingen (English: Duke of Elchingen) were created by Napoleon, Emperor of the French, for the Marshal of the Empire Michel Ney. Both were victory titles; Ney was created Duc d'Elchingen in 1808, after the Battle of Elchingen, and Prince de la Moskowa in 1813, after the Battle of Borodino (French: Bataille de la Moskowa, in reference to the Moskva River, 125 km outside Moscow).
In 1814, Ney became a peer of France. On his execution in 1815, the peerage was revoked, but it was restored in 1831. Clauses in the titles' patents of creation caused the title of Prince de la Moskowa to pass to Ney's eldest son, Joseph, and the title of Duc d'Elchingen to pass to his second son, Michel. This ensured that the two titles would never be held by the same person if there was another heir living, a similar situation to the British titles of Duke of Hamilton and Earl of Selkirk.
The two titles became united in one person in 1928 (Charles Aloys Ney, 4th Duc d'Elchingen from 1881 and 5th Prince de la Moskowa from 1928), and both became extinct with the death of the last heir in 1969.