The Mystery of the Lost Cigars (And Special Order No. 191)

(Wikipedia) Special Order 191 (the "Lost Dispatch," and the "Lost Order") was a general movement order issued by Confederate Army General Robert E. Lee in the Maryland Campaign of the American Civil War. The order was drafted on or about September 9, 1862, during the Maryland Campaign.
... About 10 a.m. on September 13, 1862 Corporal Barton W. Mitchell of the 27th Indiana Volunteers, part of the Union XII Corps, discovered an envelope with three cigars wrapped in a piece of paper lying in the grass at a campground that Hill had just vacated. Mitchell realized the significance of the document and turned it in to Sergeant John M. Bloss.
They went to Captain Peter Kopp, who sent it to regimental commander Colonel Silas Colgrove, who carried it to the corps headquarters. There, an aide to Brig. Gen. Alpheus S. Williams recognized the signature of R. H. Chilton, the assistant adjutant general who had signed the order. Williams forwarded the dispatch to Maj. Gen. George B. McClellan, the commander of the Army of the Potomac. McClellan was overcome with glee at learning planned Confederate troop movements and reportedly exclaimed, "Now I know what to do!" He confided to a subordinate, "Here is a paper with which, if I cannot whip Bobby Lee, I will be willing to go home." Continued