FREDERICK, Md. (AP) — The "lost orders" of Confederate Gen. Robert E. Lee are the latest attraction at the Monocacy (mah-NAH'-kah-see) National Battlefield near Frederick.

The handwritten, two-page document from the Library of Congress is featured in an exhibit opening Wednesday.

Lee issued the orders Sept. 9, 1862, to send troops to Boonsboro and Hagerstown, and to Martinsburg and Harpers Ferry in what was then Virginia.

Union troops found a lost copy of the orders four days later near Frederick. The document enabled Union Gen. George McClellan to plan a strategy for destroying Lee's army piece by piece.

Their forces clashed the next day on South Mountain and a few days later at Antietam. Lee had enough time to consolidate his troops, and historians disagree about the impact of the lost orders.