General Samuel Heintzelman CDV Waist up pose in uniform. Colonel of the 17th Pennsylvania Infantry, and was soon promoted to command of a division in the Army of Northeastern Virginia. He was wounded at the July 1861 Battle of Bull Run. He commanded the 3rd Corps of the Army of the Potomac in the Peninsular Campaign. His corps played a prominent role in the siege of Yorktown where Heintzelman and Division Commander Fitz John Porter were among the first to use the Union Army Balloon Corps. The corps bore the brunt of the fighting at Williamsburg and saw significant action at Fair Oaks and Oak Grove. His corps was temporarily attached to the Army of Virginia and took part in the Second Battle of Bull Run. His popularity and confidence in the army were eclipsed by the aggressive nature of his subordinate division commanders Joseph Hooker and Philip Kearney. Relieved of duty with the Army of the Potomac in late 1862, he was assigned to the defense of Washington, D.C. in command of the Department of Washington. Back mark E. & H.T. Anthony, New York.