In September 1862, Union soldiers found an official Confederate document on the battlefield and sent it up the chain of command. It turned out to be an order from Confederate commander General Robert E. Lee, which came to be known as his “lost order” or Special Order No. 191.
The order fell into Union commander General McClellan’s hands a few days before the Battle of Antietam and provided the Union army with information about the location and movement of Lee’s army. Lee had dispersed his army to capture the Union garrison and supplies at Harpers Ferry. The discovery of the lost order enabled the normally cautious McClellan to attack Lee before he could reassemble his forces. After Antietam, the withdrawal of the Confederate army back to Virginia paved the way for President Lincoln to issue the Emancipation Proclamation.
Lee had sent multiple copies of the order to his generals, as well as to Jefferson Davis and possibly Adjutant General Samuel Cooper – the copy shown here.
