The Army of Northern Virginia was the primary military force of the Confederate States of America in the Eastern Theater of the American Civil War. It was most often arrayed against the Union Army of the Potomac.------------------The name Army of Northern Virginia referred to its primary area of operation, as did most Confederate States Army names. The Army originated as the (Confederate) Army of the Potomac, which was organized on June 20, 1861, from all operational forces in northern Virginia. On July 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 in 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 Lee corresponded with Joseph E. Johnston, his predecessor in army command, prior to that date and referred to Johnston's command as the Army of Northern Virginia. Part of the confusion results from the fact that Johnston commanded the Department of Northern Virginia (as of October 22, 1861) and the name Army of Northern Virginia can be seen as an informal consequence of its parent department's name. Jefferson Davis and Johnston did not adopt the name, but it is clear that the organization of units as of March 14 was the same organization that Lee received on June 1, and thus it is generally referred to today as the Army of Northern Virginia, even if that is correct only in retrospect. ----------------- In addition to Virginians, it included regiments from all over the Confederacy, even those as far away as Texas and Arkansas. Of those, one of the most well known was the Texas Brigade, made up of the 1st, 4th, and 5th Texas, and the 3rd Arkansas, which distinguished themselves in numerous battles, perhaps most notably during their fight for the Devil's Den at the Battle of Gettysburg. Militiamen from the New Mexico and Arizona territories also served among its members.