William Tecumseh Sherman was an American soldier, businessman, educator, and author. He served as a general in the Union Army during the American Civil War (1861–1865), achieving recognition for his command of military strategy as well as criticism for the harshness of the scorched-earth policies that he implemented against the Confederate States. British military theorist and historian B. H. Liddell Hart declared that Sherman was "the most original genius of the American Civil War" and "the first modern general".

The First Battle of Bull Run, called the Battle of First Manassas by Confederate forces, was the first major battle of the American Civil War. The battle was fought on July 21, 1861, in Prince William County, Virginia, just north of what is now the city of Manassas and about thirty miles west-southwest of Washington, D.C. The Union Army was slow in positioning themselves, allowing Confederate reinforcements time to arrive by rail. Each side had about 18,000 poorly trained and poorly led troops. The battle was a Confederate victory and was followed by a disorganized post-battle retreat of the Union forces.