On January 20, 1863, Major General Ambrose E. Burnside issued Special Orders, No. 20, (AOP) confirming the appointment of Major General Franz Sigel as commander of the Grand Reserve Division of the Army of the Potomac.
Special Orders, No. 20
Headquarters Army of the Potomac.
Camp near Falmouth, Va., January 20, 1863
I. The Eleventh and Twelfth Army Corps will hereafter be known as the grand reserve division of this army, under the command of Gen. F. Sigel, U.S. Volunteers. This order to have effect from the date he was authorized to assume the command of both corps.
By command of Major-General Burnside: