Starting in November 1862, Maj. Gen. Ulysses S. Grant, commanding Union forces in Mississippi, undertook a campaign to capture the city of Vicksburg, high on the bluffs of the Mississippi River, one of two Confederate strong points (the other being Port Hudson, Louisiana) that denied the Union complete control of the Mississippi River. Grant split his 70,000-man army into two wings—one commanded by himself and one commanded by Maj. Gen. William T. Sherman. Sherman commanded the Right Wing, or XIII Corps, Army of the Tennessee, redesignated the XV Corps on December 22. His expeditionary force of 32,000 troops was organized into four divisions, commanded by Brig. Gens. Andrew J. Smith, Morgan L. Smith, George W. Morgan, and Frederick Steele.