The federal forces in and around Washington, D.C., were reorganized after the Battle of Bull Run. There was still a division between Regular Army and volunteers, but the former was gaining in size and strength. General George B. McClellan proved a masterful organizer, separating the army into brigades and divisions, and by October 1861 people were calling it the “Army of the Potomac.”

That name was actually coveted by the other side. For a time, the Confederates called their men in that vicinity by the same title. But in the spring of 1862, they carried out a reorganization and were thereafter called the “Army of Northern Virginia.”