victories. The strategically important city of Vicksburg, Mississippi was still in Confederate hands, serving as both a strong defensive position by commanding the river and as the linchpin between the two halves of the Confederacy. Union Navy elements were sent upriver from New Orleans in May to try to take the city, a move that was ultimately unsuccessful. In late June, a joint army-navy expedition returned to make another campaign against Vicksburg. Union Navy leadership decided that the city could not be taken without more infantrymen, who were not forthcoming. An attempt to cut a canal across a meander of the river, bypassing Vicksburg, failed. In late November, about 40,000 Union infantry commanded by Major General Ulysses S. Grant began moving south towards Vicksburg from a starting point in Tennessee. Grant ordered a retreat after a supply depot and part of his supply line were destroyed during the Holly Springs Raid and Forrest's West Tennessee Raid. Meanwhile, another arm of the expedition under the command of Major General William T. Sherman left Memphis, Tennessee on the same day as the Holly Springs Raid and traveled down the Mississippi River. After diverting up the Yazoo River, Sherman's men began skirmishing with Confederate soldiers defending a line of hills above the Chickasaw Bayou. A Union attack on December 29 was defeated decisively at the Battle of Chickasaw Bayou, and Sherman's men withdrew on January 1, 1863. Prelude Beginning of Grant's campaign In early 1863, Grant planned further operations against Vicksburg. Some of these plans included revisiting the 1862 canal site attempt, a new plan to cut a canal into the Mississippi River near Lake Providence, Louisiana, and navigating through bayous to bypass Vicksburg. Expeditions sent through the Yazoo River and Steele's Bayou failed to find a viable alternate route. By March 29, these alternatives were abandoned by Grant, leaving him with the choices of attacking Vicksburg from directly across the river, pulling back to Memphis and then attacking overland from the north, or marching south on the Louisiana side of the river and then crossing it below the city. Attacking the enemy from across the river, Grant could have risked heavy casualties, but pulling his men back to Memphis could have been interpreted as a retreat and politically disastrous. This led Grant to choose the southward movement. On April 29, Union Navy ships bombarded Confederate river batteries at Grand Gulf in preparation