Lee's army had proven itself victorious in northern Virginia, but elsewhere in mid-1863, the Confederacy was under pressure. To take the war to the Union, General Lee urged a counteroffensive into Pennsylvania, an attack that would end at the town of Gettysburg.
While Lee's victory at Chancellorsville diminished yet again the threat on the east coast, things were not going nearly as well in the west. Persistent Union troops worked their way down the Mississippi and were now besieging the last two Confederate centers on that vital river, Vicksburg and Port Hudson. Jefferson Davis knew that he could not let the river fall, and summoned Lee to Richmond to discuss options for relieving the besieged points. One obvious possibility would be to shift some of the Army of Northern Virginia west under Joseph Johnston, now commanding the forces east of the Mississippi, whose job it would be to relieve Vicksburg. Lee vigorously resisted this suggestion, instead proposing a major counteroffensive north with the ever-victorious Army of Northern Virginia. This could not only cause the Federal high command to divert troops from the west to the east, but could also take the war away from Virginia to allow the farmers to get their crops secured. Lee was so certain of his ability to win the civilian government officials over to his side in this discussion that as early as February 1863 he had a map of Pennsylvania as far north as Harrisburg and as far east as Philadelphia drawn up for reference. After several meetings, Confederate President Jefferson Davis decided to allow Lee to make his northern invasion and hope for the best on the Mississippi.
The Army of Northern Virginia, although depressed by Jackson's death, was in the highest of spirits. They felt themselves quite unbeatable, as did Lee and his generals. There was the question, however, of how to best fill the gap Jackson left. On May 6, Lee named A.P. Hill as temporary commander of II Corps, one of the two the army had. However, Lee felt that his corps were too large for a single general to oversee in action, and therefore at the end of May he reorganized the