Special Order 191 (series 1862), also known as the "Lost Dispatch" and the "Lost Order", was a general movement order issued by Confederate Army General Robert E. Lee on about September 9, 1862, during the Maryland Campaign of the American Civil War. A lost copy of this order was recovered on September 13 by Union Army troops in Frederick County, Maryland, and the subsequent military intelligence gained by the Union played an important role in the Battle of South Mountain and Battle of Antietam. History Drafting The order was drafted on or about September 9, 1862, during the Maryland Campaign. It gave details of the movements of the Army of Northern Virginia during the early days of its invasion of Maryland. Lee divided his army, which he planned to regroup later; according to the precise text Major General Stonewall Jackson was to move his command to Martinsburg while McLaws's command and Walker's command "endeavored to capture Harpers Ferry." Major General James Longstreet was to move his command northward to Boonsborough. Major General D. H. Hill's division was to act as rear guard on the march from Frederick. Lee delineated the routes and roads to be taken and the timing for the investment of Harpers Ferry. Adjutant Robert H. Chilton penned copies of the letter and endorsed them in Lee's name. Staff officers distributed the copies to various Confederate generals. Jackson in turn copied the document for one of his subordinates, D. H. Hill, who was to exercise independent command as the rear guard. Hill said the only copy he received was the one from Jackson. Union discovery of lost copy About noon on September 13, 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 Brigadier General Alpheus S. Williams recognized the signature of R. H. Chilton, the assistant adjutant general who had signed the order. Williams's aide, Colonel Samuel Pittman, recognized Chilton's signature because Pittman frequently paid drafts drawn under Chilton's signature before the war. Pittman worked for