Pemberton's foremost objective in prolonging the siege had been to
afford Johnston and the Confederate government time to collect
sufficient troops to raise the siege. But shortly after Grant had
invested the city, Gen. Robert E. Lee's Army of Northern Virginia began
its invasion of the North, which ended on the field of Gettysburg. No
troops could be spared from that point. To have removed troops from Lt.
Gen. Braxton Bragg's army in Tennessee would have dangerously weakened
that place in a desperate attempt to save the Mississippi. Johnston
wired Secretary of War James A. Seddon "We cannot hold both."
[Illustration: _The Surrender Site. The monument was erected and
inscribed by Union soldiers on spot where Grant and Pemberton met._]
During June, General Johnston had succeeded in increasing his force to
about 30,000, many of whom were green troops, but efforts to secure
adequate weapons, ammunition and wagons to equip the regiments had been
only partly successful. Preparing to encounter an expected move by
Johnston against his rear, Grant used reinforcements arriving from
Memphis to construct and man a strong outer defense line facing
Johnston's line of advance. Grant then had two lines of works, one to
hold Pemberton in, the other to hold Johnston out. While Seddon notified
Johnston "Rely upon it, the eyes and hopes of the whole Confederacy are
upon you, with the full confidence that you will act, and with the
sentiment that it is better to fail nobly daring, than, through prudence
even, to be inactive," Johnston notified his government on June 15 "I
consider saving Vicksburg hopeless."
On July 1, Johnston moved his army of 4 infantry and 1 cavalry divisions
to the east bank of the Big Black River, seeking a vulnerable place to
attack Grant's outer defenses. His reconnaissance during the next 3 days
convinced him that no move against the Federal position was practicable.
Receiving word of the surrender on July 4, he withdrew to Jackson.