150 years ago: The Gettysburg Campaign

 

(Wikipedia) The Gettysburg Campaign was a series of battles fought in June and July 1863, during the American Civil War. After his victory in the Battle of Chancellorsville, Confederate General Robert E. Lee's Army of Northern Virginia moved north for offensive operations in Maryland and Pennsylvania. The Union Army of the Potomac, commanded by Maj. Gen. Joseph Hooker and then (from June 28) by Maj. Gen. George G. Meade, pursued Lee, defeated him at the Battle of Gettysburg, but allowed him to escape back to Virginia.
Lee's army slipped away from Federal contact at Fredericksburg, Virginia, on June 3, 1863. While they paused at Culpeper, the largest predominantly cavalry battle of the war was fought at Brandy Station on June 9. The Confederates crossed the Blue Ridge Mountains and moved north through the Shenandoah Valley, capturing the Union garrison at Winchester, Virginia, in the Second Battle of Winchester, June 13–15. Crossing the Potomac River, Lee's Second Corps advanced through Maryland and Pennsylvania, reaching the Susquehanna River and threatening the state capital of Harrisburg. However, the Army of the Potomac was in pursuit and had reached Frederick, Maryland, before Lee realized his opponent had crossed the Potomac. Continued