Louis Nicolas d'Avout, 1804, (1839). 'Davoust (L. Nicolas) Prince d'Eckmuhl, Mar?chal de France'. Portrait of Louis Nicolas d'Avout (1770-1823), Duke of Auerstaedt and Prince of Eckm?hl. D'Avout (also known as Davoust or Davout) was a Marshal of France during the Napoleonic Era. Because of his prodigious talent for war and his reputation as a stern disciplinarian, he was also known as the Iron Marshal. He was the only Napoleonic Marshal to finish his military career undefeated in battle. From "Galerie Des Mar?chaux De France. D?di?e ? l'Arm?e de Terre et de Mer" (Gallery of the Marshals of France. Dedicated to the Army of Land and Sea), by Charles Gavard. [De Fain, Paris, 1839]