Antietam

The battle of Antietam, fought on September 17th, 1862, by the Union army of the Potomac, commanded by the infamously "aggressive" in extremely heavy air quotes General George McClellan, and The Confederate Army of Northern Virginia commanded bye Robert E. Lee. Historically the battle of Antietam was won by the Union and led to Abraham Lincoln signing the Emancipation Proclamation being brought into effect on January 1st 1863. For the sake of story you may be whoever, McClellan, Lee, I don't give a crap. have fun!