Confederate General Robert E. Lee's first invasion of the North hinged on eliminating the Harpers Ferry garrison. To do so Lee devised Special Orders 191 and divided his force of 40,000 into four parts. Three columns marched from near Frederick, Maryland, 22 miles northeast of here, to seize the three mountains surrounding Harpers Ferry, while the fourth moved north and west toward Hagerstown. Following victory at Harpers Ferry, Lee intended to reunite his army and continue the invasion into Pennsylvania. Lee assigned Major General "Stonewall" Jackson to command the Harpers Ferry attack. Jackson's columns faced challenging barriers, including long sweeping marches over mountain passes and across the Potomac River, and once here, "Stonewall's" soldiers had to scale the surrounding heights. Victory demanded coordination, communication, and convergence, because any lapse would enable the Federals to escape.