<P> After winning the Battle of Chancellorsville, the Army of Northern Virginia lost Lt. Gen. Stonewall Jackson to pneumonia following a friendly fire accident . His death was a blow to the morale of the Confederate army, as he was one of its most popular and successful commanders . Two months later, Robert E. Lee had no general with Jackson's audacity available at the Battle of Gettysburg . Many historians argue that Jackson might have succeeded in seizing key battlefield positions (such as Culp's Hill and Cemetery Hill at the end of day one) that his replacements were unable or unwilling to take . Lee himself shared this belief and is said to have told his subordinate generals on different occasions that they should have acted like Jackson would have . </P> <P> On July 4, 1863, the most important Confederate stronghold on the Mississippi River at Vicksburg, Mississippi surrendered to General Ulysses S. Grant . The previous day, Maj. Gen. George Meade had decisively defeated Robert E. Lee at Gettysburg, Pennsylvania . These nearly simultaneous battles are the events most often cited as the ultimate turning points of the entire war . </P> <P> The loss of Vicksburg split the Confederacy in two, denying it any further movement along or across the Mississippi River and preventing supplies from Texas and Arkansas that might sustain the war effort from passing east . As President Lincoln had stated, "See what a lot of land these fellows hold, of which Vicksburg is the key! The war can never be brought to a close until that key is in our pocket...We can take all the northern ports of the Confederacy and they can defy us from Vicksburg ." Furthermore, the 30,000 soldiers who surrendered with the city were a significant loss to the military manpower of the Southern cause . </P> <P> Gettysburg was the first major defeat suffered by Lee . The three - day battle witnessed Union forces decisively repel his second invasion of the North and inflicted serious casualties on his Army of Northern Virginia . In fact, the National Park Service marks the point at which Pickett's Charge collapsed, a copse of trees on Cemetery Ridge, as the high - water mark of the Confederacy--the northernmost point reached by any major Confederate military incursion . From this point onward, Lee attempted no more strategic offensives . Although two more years of fighting and a new, more aggressive general - in - chief (Grant) was required to fully subdue the rebellion, the Army of the Potomac gained an indomitable initiative at Gettysburg that makes the eventual end at Appomattox Court House in 1865 seem inevitable in hindsight . While Gettysburg was seen by military and civilian observers at the time as a great battle, those in the North had little idea that two more bloody years would be required to finish the war . Lincoln was distraught at Meade's failure to intercept Lee's retreat, believing that to have done so would have ended the conflict . </P>

What city became the souths last stronghold in the western theater