164 years ago today Robert E. Lee did something breathtaking and enormously risky. Riding the momentum of his victory at Second Bull Run, he began marching his ragged, barefoot army across the Potomac River and onto Northern soil, launching the invasion that would climax two weeks later on the bloodiest single day in American history.
The timing seemed perfect for the Confederacy. Lee had just crushed two Union armies in Virginia, the enemy was demoralized and huddled in the defenses of Washington, and the fields of the North were ripe with the harvest. Lee reasoned that a bold stroke across the Potomac could accomplish enormous things. It would carry the war off of war-torn Virginia and let his men feed off Maryland's farms. It might rally the slave state of Maryland to the Confederate cause. And above all, a decisive victory won on Northern soil might finally convince Britain and France to recognize the Confederacy, and might break the will of the Northern public in that crucial election year.
So on September 4, 1862, the lead elements of the Army of Northern Virginia began fording the Potomac, and over the following days the whole army crossed and concentrated around the town of Frederick, Maryland. Confederate bands played Maryland, My Maryland as the columns splashed across, hoping to win the state's heart. But the reality was sobering. Lee's army was in terrible physical condition, exhausted, hungry, and so short of shoes that thousands of men marched into Maryland barefoot, leaving bloody footprints on the roads. Straggling was severe, and the invading army was smaller and frailer than it looked on paper.
Lee's plans hinged on clearing the Union garrison from Harpers Ferry to secure his supply line, and to do it he made the audacious decision to divide his already outnumbered army into several pieces. It was a gamble that nearly paid off brilliantly, and then nearly ended in disaster when a copy of his secret orders fell into Union hands, wrapped around a bundle of cigars, and handed George McClellan a road map to the scattered Confederate army.
That is the story that unfolds over the next two weeks. This crossing on September 4 was the first step of the Maryland Campaign, the road that led through the fights at South Mountain and the capture of Harpers Ferry to the cornfield and the sunken road at Sharpsburg, where on September 17 the two armies would collide at Antietam and more Americans would fall in a single day than on any other day in the nation's history.