On June 20, 1861, Brigadier General P. G. T. Beauregard issued General Orders, No. 20 referring, for the first time, to the troops under his command as the Army of the Potomac.
General Orders, No. 20.
Hdqrs. Army of the Potomac
Manassas Junction, Va., June 20, 1861
The following is announced as the organization of the First Corps of the Army of the Potomac, which, for convenience, will be the designation of the troops of this command:
I. The First Brigade will consist of Gregg’s Bacon’s Kershaw’s and Cash’s regiments, South Carolina volunteers, Brig. Gen. M. L. Bonham commanding.
II. The Second Brigade, commanded by Brig. Gen. R. S. Ewell, Provisional Army of the Confederate States, will be formed by Seibel’s and Rode’s regiments of Alabama volunteers, and Seymour’s regiment of Louisiana volunteers.
III. The Third Brigade will consist of Jenkin’s regiment of South Carolina volunteers, and Featherstone’s and Burt’s regiments of Mississippi volunteers, Brig. Gen. D. R. Jones, Provisional Army, Confederate States, commanding.
IV. The Fourth Brigade, Col. G. H. Terrett, Provisional Army of Virginia, commanding, will be formed of Moore’s, Garland’s, and Corse’s regiments of Virginia volunteers.
V. The Fifth Brigade will consist of Cocke’s Preston’s, and Withers’ regiments of Virginia volunteers, Col. P. St. George Cocke, Virginia volunteers, commanding.
VI. The Sixth Brigade, Col. J. A. Early, commanding, will be formed of Early’s and Kemper’s Virginia volunteers, and Sloan’s regiment of South Carolina volunteers.
VII. The several commanders of brigades thus announced will organize their general and personal staff, as far as practicable, without delay, and will make the necessary returns and reports direct to these headquarters.
VIII. In the absence of any of the special brigade commanders, the senior colonel present will assume command of the brigade.
By order of Brigadier-General Beauregard:
Acting Assistant Adjutant-General