On Monday, May 18, 1863 Ulysses Grant’s Federal army, triumphant at Champion Hill and the Big Black River, began to envelope Vicksburg. John Pemberton was ordered by General Joseph Johnston to evacuate Vicksburg, but knowing that President Jefferson Davis wished to have the city defended, Pemberton with the concurrence of his subordinate officers decided to stay.
Given his prior actions and both the complexity and potential human cost of having thousands of troops attempt to break out of the growing, Union envelopment, Pemberton had little choice but to remain in Vicksburg and hope that Joseph Johnston’s Confederates could come to Vicksburg’s assistance.
In fact, Jefferson Davis was appealing for Mississippi civilians and militia to join Johnston in order to increase his forces so as to relieve beleaguered Vicksburg.