Confederate general Thomas Jonathan Jackson had been a virtual unknown upon his arrival at the front line of First Bull Run, but by the spring of 1862, thanks to his actions at that battle, "Stonewall" was already becoming known across the battlefields. Ultimately, it would be the Valley Campaign of 1862 that made him a legend. In the early months of 1862, Jackson was given command of an army numbering about 17,000 in the Shenandoah Valley. His task was daunting. The loss at Bull Run prompted a changing of the guard, with George B. McClellan, the "Young Napoleon", put in charge of reorganizing and leading the Army of the Potomac. That spring, the Army of the Potomac conducted an ambitious amphibious invasion of Virginia's Peninsula, circumventing the Confederate defenses to the north of Richmond by attacking Richmond from the southeast. General Johnston's outnumbered army headed toward Richmond to confront McClellan, but the Union still had three armies totaling another 50,000 around the Shenandoah Valley, which represented a threat to Richmond from the north. It was these armies that Jackson would be tasked with stopping. Jackson would go on to lead his undermanned army through what military strategists and historians consider the most incredible campaign of the Civil War.