Larrey was made a Commander of the Légion d'honneur on 12 May 1807. He joined in the Battle of Aspern-Essling, where he operated on Marshall Jean Lannes and amputated one of his legs in two minutes. He became the favorite of the Emperor, who commented, "If the army ever erects a monument to express its gratitude, it should do so in honor of Larrey", he was ennobled as a Baron on the field of Wagram in 1809. In 1811, Baron Larrey co-led the surgical team that performed a pre-anesthetic mastectomy on Frances Burney in Paris. Her detailed account of this operation gives insight into early 19th century doctor-patient relationships, and early surgical methods in the home of the patient. Larrey was involved in the French invasion of Russia.