 Pitman served as a private in the 22nd Regiment Massachusetts Volunteer Infantry , Company H. This regiment was also named the " Henry Wilson 's Regiment " after Col. Henry Wilson , who commanded the unit in 1861 . Col. William S. <unk> was the commander during Pitman 's brief term of service . The regiment was part of the V Corps of the Army of the Potomac under the command of Major General George B. <unk> . During this period , the regiment fought in the Second Battle of Bull Run and was involved in the Maryland Campaign fighting in the Battle of Antietam , the <unk> single @-@ day battle in American history , and the Battle of <unk> . His regiment was on the march to the Battle of Fredericksburg when Pitman was captured by Confederate troops . 
