The First Battle of Bull Run, fought on July 21, 1861, was the first major battle of the American Civil War. It took place near Manassas, Virginia, and involved Union forces led by General Irvin McDowell against Confederate troops commanded by General Pierre G. T. Beauregard and General Joseph E. Johnston. The battle was intended to be a quick victory for the Union, but it ended in a surprising defeat. The battle revealed the war's potential for brutality and the need for better training and preparation. Many civilians came to watch, expecting a short conflict, but they witnessed chaos as the Union army retreated. The outcome boosted Confederate morale and marked a turning point in the war, leading to a more prolonged and intense conflict.