General Robert E. Lee, the Confederate commander of the Army of Northern Virginia, invaded Union territory in an attempt to persuade the United States into a negotiated peace after a hoped-for decisive and damaging attack on Northern soil. It was also believed that a notable Southern victory in Union territory might have resulted in financial support and recognition of the Confederate cause from England or France. General Lee's first invasion of the North, which took place in Maryland during September of 1862, was repulsed by Union forces at the Battle of Antietam, but it was followed by a second invasion by Lee into Pennsylvania during the months of June and July in 1863.
General Lee's second invasion of the North ended with a Union victory at the battle of Gettysburg, the bloodiest battle of the American Civil War with casualties estimated at more than 50,000 for both sides. This battle was the largest single military engagement to take place in the Western Hemisphere. The Confederate defeat at Gettysburg signaled a turning point in the war, and Lee's Army of Northern Virginia was forced into retreat. Four months after the battle, the scene of the pivotal engagement was commemorated by U.S. President Abraham Lincoln's most well-known oration, the Gettysburg Address.