 Complete the following phrase:  On May 13, 1863, Union forces won the first Battle of Jackson, forcing Confederate forces to flee northward towards Canton. Subsequently, on May 15 Union troops under William Tecumseh Sherman burned and looted key facilities in Jackson. After driving the Confederates out of Jackson, Union forces turned west once again and soon placed Vicksburg under siege. Confederates began to reassemble in Jackson in preparation for an attempt to break through the Union lines now surrounding Vicksburg. Confederates marched out of Jackson to break the siege in early July. However, unknown to them, Vicksburg had already surrendered on July 4. Union Army general Ulysses S. Grant dispatched Sherman to meet the Confederate forces. Upon learning that Vicksburg had already surrendered, the Confederates retreated back into Jackson, thus beginning the 