Autograph Letter Signed, to Madame de Sy, about her son and his distinguished military service. In French. 1 page 8 x 6 inches, in good condition. Zierenberg [Germany], 3 February [?] 1760. Charles Joseph Hyacinthe du Houx de Vioménil, Marquis of Vioménil (1734 – 1827), Marshal of France. Promoted maréchal de camp in 1780, Viomesnil served under Rochambeau in America during the Yorktown campaign. After his return from the American Revolutionary War he was made inspector-general of the cavalry (1783–1788). In 1789–1790 he served as governor of Martinique.