On the evening of May 1, 1863, General Robert E. Lee knew several facts about the military situation confronting him:
1. His army was between two forces, Hooker with approximately 70,000 men at Chancellorsville and Sedgwick south of Fredericksburg with approximately 40,000 men. Confronting Sedgwick he had Early with about 11,000 men and confronting Hooker Lee had around 40,000 men.
2. If Sedgwick and Hooker attacked aggressively Lee’s army could be destroyed between them.
3. Neither Sedgwick nor Hooker had demonstrated much appetite for attack. Hooker had launched a brief attack the morning of May 1, but had quickly called it off, Hooker being content to defend against Lee.
4. Lee now had the initiative, ceded to him miraculously by the man who commanded a combined force more than twice the size of Lee’s.
5. What to do with the initiative was the question. How could Lee overcome such a grave disparity in numbers?
The solution was found at an evening conference that Lee had with Jackson. Go here to see a video on the conference. Jackson believed that Hooker might retreat, but Lee reasoned that Hooker had too much political capital invested in the attack. Hooker’s army would remain at Chancellorsville and Lee would attack him if a plan could be devised that made such an attack practicable. At that time Lee’s son, cavalry General Fitzhugh Lee, rode up with the news that the Union right was “in the air” and that a flank attack was feasible.
After ascertaining that a route could be found around the Union right in the Wilderness, Lee ordered Jackson to make the attack. Jackson advised Lee that he would make the attack by marching to the rear of the Union right. This would leave Lee with about 12,000 men confronting an army of 70,000 for most of May 2, 1863 while Jackson made his long flanking march. Such a thought would have made almost all generals reject the plan outright. Lee however was a military gambler, he had to be since he never had numbers and resources in his favor. Lee also trusted Jackson implicitly, his right arm. The attack would be made on the morrow.