American Civil War: Robert E. Lee resigns his commission in the United States Army in order to command the forces of the state of Virginia.

Civil War Maryland Campaign: General Robert E. Lee takes the Army of Northern Virginia, and the war, into the North.

American Civil War: Union soldiers find a copy of Robert E. Lee's battle plans in a field outside Frederick, Maryland. It is the prelude to the Battle of Antietam.

American Civil War: George B. McClellan halts the northward drive of Robert E. Lee's Confederate army in the single-day Battle of Antietam, the bloodiest day in American history.

American Civil War: At the Battle of Fredericksburg, Confederate General Robert E. Lee defeats the Union Major General Ambrose E. Burnside.

American Civil War: following his defeat in the Battle of Gettysburg, General Robert E. Lee sends a letter of resignation to Confederate President Jefferson Davis (which is refused upon receipt).

Arlington National Cemetery is established when convert 200 around Arlington Mansion (formerly owned by Confederate General Robert E. Lee) are officially set aside as a military cemetery by U.S. Secretary of War Edwin M. Stanton.

American Civil War: The Siege of Petersburg is broken – Union troops capture the trenches around Petersburg, Virginia, forcing Confederate General Robert E. Lee to retreat.

American Civil War: Robert E. Lee surrenders the Army of Northern Virginia (26,765 troops) to Ulysses S. Grant at Appomattox Courthouse, Virginia, effectively ending the war.

American Civil War: A day after his surrender to Union forces, Confederate General Robert E. Lee addresses his troops for the last time.