Army of Northern Virginia 20 and July 21, the Army of the Shenandoah and forces from the District of Harpers Ferry were added. Units from the Army of the Northwest were merged into the Army of the Potomac between March 14 and May 17, 1862. The Army of the Potomac was renamed "Army of Northern Virginia" on March 14. The Army of the Peninsula was merged into it on April 12, 1862. Robert E. Lee's biographer, Douglas S. Freeman, asserts that the army received its final name from Lee when he issued orders assuming command on June 1, 1862. However, Freeman does admit that
Fourth Corps, Army of Northern Virginia Commanded by temporary Lt. General Anderson, it was made up of units that before had served around Richmond and Petersburg as part of General Beauregard's Department of North Carolina and Southern Virginia. The Fourth Corps spent the winter of 1864/5 encamped around Petersburg as part of the Army of Northern Virginia. In April the Army of the Potomac, under General Ulysses Grant, broke through the defences and successfully concluded the siege of Richmond, initiating the start of the Appomattox Campaign. The Fourth Corps retreated with the rest of General Lee's Army but was largely destroyed in the Battle of Sailor's