Why did confederate general Robert E. Lee decide to invade Union territory during the Civil War?

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.