Sedgwick's success endangered Lee, and, unless Fredericksburg were regained, the battle was lost to the Rebels. Lee says:—
"The enemy had so strengthened his position near Chancellorsville that it was deemed inexpedient to assail it with less than our whole force, which could not be concentrated until we were relieved from the danger that menaced our rear. It was accordingly resolved still further to reinforce the troops in front of General Sedgwick, in order, if possible, to drive him across the Rappahannock. Accordingly, on the 4th, General Anderson was directed to proceed with his remaining brigades to join General McLaws, the three divisions of Jackson's corps holding our position at Chancellorsville. Anderson reached Salem Church about noon, and was directed to gain the left flank of the enemy and form a junction with Early."[39]
Half of the Rebel army was arrayed against Sedgwick, who held his ground through the 4th till night. Early, during the day, retraced his steps up the Telegraph road, and, finding that Sedgwick had moved out to Salem Church, and that the fortifications were unoccupied, took possession, and thus cut Sedgwick's communications with Falmouth. When Anderson arrived he had no alternative but to retreat by Banks's Ford, where he crossed the river without loss during the night. Hooker also recrossed, took up his bridges, and the army returned again to its camp.
In reviewing this battle, it is apparent that Hooker's movement to Chancellorsville was a surprise to Lee. It was excellently planned and efficiently executed,—each corps reaching its assigned position at the time appointed by the Commander-in-chief. It is plain that Hooker's departure from his original intention—to await an attack from Lee—was the cause of the disaster at the beginning of the engagement. Sickles's corps and Barlow's brigade being absent, the balance of the Eleventh Corps had no supports; and yet by Bushbeck's brigade and Dilger's battery, with such assistance as was given by a few brave men of the other brigades, Jackson's right was not only held in check, but thrown into confusion. Howard's statement of the case presents the matter in its true light.
Thus reads his report:—
"Now, as to the cause of this disaster to my corps.
"1st. Though constantly threatened, and apprised of the moving of the enemy, yet the woods were so dense that he was able to mass a large force, whose exact whereabouts neither patrols, reconnoissancers, nor scouts ascertained. He succeeded in forming a column to and outflanking my right.
"2d. By the panic produced by the enemy's reverse fire, regiments and artillery were thrown suddenly upon those in position.
"3d. The absence of General Barlow's brigade, which I had previously located in reserve and en echelon, with Colonel Von Gilsa's, so as to cover his right flank.
"My corps was very soon reorganized, near Chancellorsville, and relieved General Meade's corps on the left of the line, where it remained till Thursday morning."[40]