It starts when General Robert E. Lee takes command and after the second battle of Bull Run. Lee has won seven days. The battle of Manasses and he is wanting to invade the north. One of his motives for this is that he wants to get the fighting out of the war-torn state of Virginia and enter a campaign into the north to interrupt the north's supply lines. This campaign was considered to be the south's best chance to invade the north. This campaign was of great significance to the south because if General Lee could beat McClellan in the north then either Great Britain or France would enter the war on the side of the confederacy. In the start of his campaign General Lee moved across the Potomac river and then split his army into four or five sections. He sent most of his army with General Jackson to Harpers Ferry so they could seize it and open up supply routes.
General McClellan the general of the Union army had a stroke of luck. His soldiers had found a copy of General Lee's Deployments wrapped in three cigars found in a field. McClellan though was too cautious and moved too slow so he was not able to take the full advantage of his copy of Lee's Deployment's, so he was unable to stop Jackson at Harper's Ferry. General Lee pulls his army together at Sharpsburg and he is outnumbered by the union troops two to one. The battle was fought in three sections. The first was in the morning at Dunkard Church, then in the afternoon it was at sunken road, the confederacy was attacked here by the union from right to left on a four-mile front. The last section of the battle was that evening at Burnick bridge.