Irvin McDowell was a prominent figure during the early months of the Civil War. With so much at stake, he was called upon to lead the Union’s largest Eastern Theater army. Pressed by the media and President Abraham Lincoln to move into Virginia and defeat the Confederates gathering there, McDowell led his neophyte army out to the plains of Manassas and was soundly defeated. McDowell went on to hold an independent command in northern Virginia during the Peninsula Campaign and serve in the Army of Virginia under Maj. Gen. John Pope during the disastrous Second Bull Run Campaign. Despite his significant contributions, a lack of personal papers left him in obscurity.

At the outbreak of the Civil War, on May 14, 1861, Irvin McDowell was promoted to the rank of Brigadier General as a result of political connections to the Secretary of the Treasury, Salmon P. Chase.  Although he had never before commanded troops in combat, McDowell, facing political pressure, attacked Confederate forces at the First Battle of Manassas where he was consequently defeated.  After the defeat, General George B. McClellan was made commander of the newly formed Army of the Potomac, and McDowell was detached from the army to protect Washington, DC.  McDowell would later command a corps at the Second Battle of Manassas, which resulted in another defeat.  On July 1, 1864, McDowell was put in command of the Department of the Pacific and was relatively inactive for the remainder of the war.