<a href="https://en.wikipedia.org/wiki/American_Civil_War" id="mwiw" rel="mw:WikiLink" title="American Civil War">American Civil War</a>: <a href="https://en.wikipedia.org/wiki/Union_(American_Civil_War)" id="mwjA" rel="mw:WikiLink" title="Union (American Civil War)">Union</a> soldiers find a copy of <a href="https://en.wikipedia.org/wiki/Robert_E._Lee" id="mwjQ" rel="mw:WikiLink" title="Robert E. Lee">Robert E. Lee</a>'s <a href="https://en.wikipedia.org/wiki/Special_Order_191" id="mwjg" rel="mw:WikiLink" title="Special Order 191">battle plans</a> in a field outside <a href="https://en.wikipedia.org/wiki/Frederick,_Maryland" id="mwjw" rel="mw:WikiLink" title="Frederick, Maryland">Frederick, Maryland</a>. It is the prelude to the <a href="https://en.wikipedia.org/wiki/Battle_of_Antietam" id="mwkA" rel="mw:WikiLink" title="Battle of Antietam">Battle of Antietam</a>.