The Battle of Bull Run was the first major civil war battle fought on July 21, 1861 at Prince William County Virginia. The battle was known as the battle of first "manassas" by the confederates. The union arrived at the battle after two days of marching in hot whether. There were 18,000 poorly trained men on each side of the war. There was also a second battle of Bull Run. Also the second battle lasted two days, and the confederate won. This is the battle that Thomas Jonathan Jackson got the name "Stonewall" Jackson.