When McClellan entered upon his Peninsular Campaign in 1862 the important duty of defending Washington from the army of "Stonewall" Jackson fell to the corps commanded by Banks.
It was eventually decided that General Banks was to oppose "Stonewall" Jackson in the Shenandoah Valley, Fremont to hold western Virginia against the same general's enterprise, and McDowell with a strong corps to advance overland to meet McClellan, who, with the main army, was to proceed by sea to Fortress Monroe and thence to advance on Richmond.
Here Stonewall Jackson lay with a small force, and in front of him at the outlet of the valley was Banks, while Fremont threatened him from West Virginia.
Stonewall Jackson was mortally wounded, but his men and those of Longstreet's who had remained with Lee defeated Hooker and forced him to retire again beyond the Rappahannock, though he had double Lee's force.
Henderson, Stonewall Jackson and the American Civil War (London, 1898) and The Science of War, chapters viii.