The First Battle of Bull Run (or Battle of Manassas) would be the first major engagement between the Union and Confederacy. Fought in Virginia, on southern soil, the Confederate forces defeated the Union thanks to their knowledge of the terrain (land) and skilled leader, Thomas Jackson. Jackson would be given the nickname, "Stonewall" because the Union army could not penetrate his forces. The Confederate victories early in the war gave them confidence and showed the Union this war would not be over in the few months as they expected.