French-American soldier (1833–1880) who was captured by John S. Mosby’s guerrillas in 1864 and spent the rest of the war as a prisoner in Danville. Civil War–dated ALS signed “A. N. Duffie act. Brig commanding 1st Cav. Brig.,” 7.5 x 9.5, March 23, 1863. Letter to a general. In part: “The 1st R. I. Cav. becomes pretty low and it is my duty as his former commander to ask…that you do all in your power to fill it up before the spring Campaing [sic].” In fine condition, with one horizontal mailing fold passing through the bottom of the signature, and scattered creases. RR Auction COA.