Group of Provost Guards at Headquarters, Army of the Potomac (US Civil War) This work, titled "Group of Provost Guards at Headquarters, Army of the Potomac," is a historic image depicting members of the military police, known as provost guards, within the Headquarters of the Army of the Potomac during the United States Civil War. The specific timeframe for this photograph is not clearly stated, but it falls under the broader context of the American Civil War which took place from 1861 to 1865. The Army of the Potomac was the primary Federal field army in the Eastern Theater of the Civil War and was instrumental in many significant battles. This image provides a snapshot of the daily life and uniforms worn by these provost guards, playing an important role in documenting military history during this turbulent period.