The letter, dated 20 April 1822, to the Marquis de Montchenu states the Emperor's thankfulness and appreciation of the services rendered by the Marquis in observing Napoleon's conduct in St. Helena for the years 1818-1821: "Sa Majesté l'Empereur désirant reconnoitre les services, que Vous Lui avez rendus ... dans les fonctions de Commissaire d'Autriche à St. Hélène, ... depuis l'année 1818 jusqu'à l'année 1821, a daigné Vous destiner, Monsieur le Marquis, une boëte ornée de son portrait et enrichie de Diamants ... ". The box together with the letter signed by the Austrian Chancellor Metternich was presented by Baron de Vincent, the Austrian ambassador in Paris on 2 May 1822

Claude Martin Henri, Marquis de Montchenu (1757-1831), was an officer. Louis XVIII ordered him to St. Helena in September 1815 to report any of Napoleon's movements. At the same time he acted as a 'Commissaire d'Autriche ad interim' for which services he was later presented this snuff-box