150 years ago today, the Reserve Brigade was born.  In Cavalry Corps, Army of the Potomac General Order No.4, Brigadier General George Stoneman laid out the organization of the newly-created Cavalry Corps.  He was assigned command of the corps five days before on February 7th.  The order was written by Assistant Adjutant General A. J. Alexander, on detached duty from his position as a captain in the 3rd U.S. Cavalry.  I have omitted the sections that do not apply to the Reserve Brigade.

“February 12, 1863.  General Orders No. 4, Headquarters Cavalry Corps.

“II. The cavalry of the corps shall be organized as follows: …  The Reserve Brigade, Brig. Gen. John Buford commanding. – First United States, Second United States, Fourth United States, Fifth United States, and Sixth United States.”

This formation wasn’t nearly as powerful as it looked on paper.  Only one squadron of the 4th Cavalry was present with the army, the remainder serving in the western theater.  The remaining regiments were understrength and led by junior officers.  This will be examined in a separate post.

The idea of a cavalry reserve was not a new one in the Army of the Potomac.  Under McClellan, it appeared to mean simply, where to put the cavalry regiments he hadn’t given to someone else.  During the previous year’s campaigning, it had consisted primarily of the regular regiments and a select few volunteer regiments.  The two small brigades of the cavalry reserve had borne the brunt of the campaigning on the peninsula.

“III. The Reserve will be encamped in the vicinity of general headquarters.”

At the time the order was published, Cavalry Corps headquarters was located near White Oak Church.  Its picket posts extended over twenty miles from this location, as far as Banks and United States Fords on the Rappahannock River.

“IV. A detail of one squadron will be furnished to each of the corps of this army to act as orderlies, messengers, &c. … The details for these and general headquarters will be furnished from the Reserve Brigade.”

The creation of the Cavalry Corps did not immediately ease the burden of the multitude of orderly taskings to commanders of the infantry formations.  The burden of the squadron details for Cavalry Corps headquarters and headquarters, Army of the Potomac fell on the Reserve Brigade initially.  Army Headquarters duty was performed by Companies A & E, 4th U.S. Cavalry.  Cavalry Corps headquarters duty rotated among the other regiments.

“V.  The general commanding the corps is desirous that every legitimate means within the reach of the officers and men under his command may be made use of to fit and perfect themselves for the most vigorous and rapid movements.  Requisitions have been made for pack-saddles sufficient to supply the wants of the whole command, and the general gives this timely notice to all that it is his intention to dispense with the use of wagons in all active field service of cavalry.”

This paragraph was more a statement of intention to wield the corps as an active and offensive organization than a set of instructions to subordinate units.  The pack-saddle concept, though attempted during Stoneman’s Raid in May, never really came to fruition.

“VI. All horses permanently disabled, or which cannot by the means of treatment be made available within a reasonable time, will be turned over to the quartermaster’s department after proper condemnation by competent authority.”

I am really not sure why this was included in the order, unless it had become a problem.  Reporting numbers of unserviceable horses per company in each regiment was a requirement in the regular regiments prior to the war, and hadn’t been discontinued.

Sources: OR, Vol. 25, pt. 2, pgs. 71-72

Frank Welcher, The Union Army, pg 516