A document signed by President Abraham Lincoln in the weeks after the Battle of Antietam was returned to the National Archives Thursday.
The November 1862 letter signed by three surgeons in Hagerstown, Md., asked Lincoln to appoint a chaplain to tend to wounded and dying soldiers after the battle, and Lincoln signed his approval.
Auctioneer Bill Panagopulos, who helped negotiate the return, handed the documents over to David Ferriero, archivist of the United States.
Investigators spotted the documents in an auction dealer's catalog in 2009. Officials said they may have been taken while in the custody of the War Department.
Antietam was the bloodiest one-day battle in American history, leaving about 23,000 soldiers killed, wounded or missing on Sept. 17, 1862.