Final answer:
The First Battle of Bull Run, occurring on July 21, 1861, led to an unexpected Confederate victory, causing a reconsideration of Northern war aims and a realization of the war's potential duration and complexity.
Step-by-step explanation:
Summary of the Battle of Bull Run
The First Battle of Bull Run, also known as First Manassas, was a significant conflict during the American Civil War that took place on July 21, 1861, in Prince William County, Virginia, near Manassas. It pitted the forces of the Confederate Army, led by Brigadier General P.G.T. Beauregard and Brigadier General Joseph E. Johnston, against the Union Army, commanded by Brigadier General Irvin McDowell. Despite initial Union attacks, the Confederate forces emerged triumphant, resulting in 1,982 Confederate casualties and 2,896 Union casualties. This unexpected victory shook Northern morale and quashed the optimism that the war would end quickly and decisively in the Union's favor.
Following the victory at Bull Run, prominent abolitionists like Frederick Douglass pressed for the Union to commit to the abolition of slavery as a war aim. The battle revealed the depth of the Southern commitment to their cause and laid bare the North's underestimation of the Confederacy's resistance. The subsequent Second Battle of Bull Run, following General Lee's campaign to take the fighting into Northern territory, ended again in a Confederate victory, intensifying the struggle and leading to further Northern reassessment of their strategy and objectives in the war.