After the greatest Confederate victory of the war at Chancellorsville in May 1863, the Army of Northern Virginia commander, General Robert E. Lee, decided that the time was right for a second invasion of the North. There were several reasons for making this decision.
- An invasion of the North would force the Union army to withdraw troops from the Siege of Vicksburg, the South's most strategic Mississippi River port in the Western theatre of the war.
- An invasion would throw a monkey wrench into Union plans for its summer battle strategies in Virginia.
- Lee hoped to head west and then northward toward Baltimore with the hopes of capturing that city and Philadelphia, before heading south to attack Washington, D. C. Lee hoped to trap the Union Army of the Potomac and destroy it once and for all.
- Lee's army could live off of the fertile land in Pennsylvania and Maryland, which had not been ravaged by the war as in Virginia. Lee also hoped to recruit several thousand Confederate sympathizers in Maryland to join his army.
- A major victory on Northern soil might bring international recognition to the Confederate States, which could also bring financial aid and military support from other countries.
Lee never planned to fight at the little college town of Gettysburg, Pennsylvania, and he had given specific orders to his corps and division commanders not to force a major action. When General J. J. Pettigrew's brigade met resistance in Gettysburg on July 1--while reportedly searching for shoes for his many barefoot troops--from the Federal cavalrymen under General John Buford, he reported the news to his division commander, General Henry Heth. Heth, believing that the Federal force was small, sent two brigades to confront Buford, who resisted until infantry arrived on the scene. The first stage of the battle was underway.
Lee's army missed the opportunity to win the battle on the night of the first day when Lietenant General Dick Ewell failed to understand Lee's "suggestion" to take the undefended and strategic Cemetery Hill. Ewell, who had replaced General T. J. "Stonewall" Jackson as one of Lee's new corps commanders, believed his men were too tired and did not take Lee's suggestion as an order. The Federals soon captured Cemetery Hill with no Confederate resistance. Both sides fought to a deadlock during the bloody attacks on July 2, marked by the determined stand by a few hundred Union troops under the command of Colonel Joshua Chamberlain on Little Round Top.
Lee's decision to make the ill-fated Pickett's Charge against the Union center on July 3 was probably his biggest mistake of the war, but Lee believed that his troops were invincible and that the 13,000 infantrymen would be able to pierce the Union line. He refused to listen to his trusted corps commander Lieutenant General James Longstreet, who begged Lee to make a strategic retreat and dig in, forcing the Federals to attack an entrenched position. But Lee would not listen: Pickett's Charge was a fatal disaster, and Lee's once proud army was never the same again.