The Army of Northern Virginia was the primary military force of the Confederate States during the American Civil War. Established in 1861, it was commanded by General Robert E. Lee for most of its existence. The army played a crucial role in several significant battles, including the Battle of Gettysburg and the Battle of Antietam. This army was known for its skilled leadership and tactical maneuvers, often facing larger Union forces. It operated mainly in the eastern theater of the war, defending the Confederate capital of Richmond, Virginia, until its surrender in 1865, marking a pivotal moment in the conflict.