The Battle of Kennesaw Mountain was fought on June 27, 1864, during the Atlanta Campaign of the Civil War. It was the most significant frontal assault launched by Union Maj. Gen.William T. Sherman against the Confederate Army of Tennessee under Gen. Joseph E. Johnston, ending in a tactical defeat for the Union forces. Strategically, however, the battle failed to deliver the result that the Confederacy desperately needed—namely a halt to Sherman's advance on Atlanta. The battle only lasted about two hours, but Sherman's armies suffered about 3,000 casualties in that short time. The confederates lost only 1,000, in comparison. On July 8, Sherman outflanked Johnston again by sending Schofield to cross the Chattahoochee near the mouth of Soap Creek. The last major geographic barrier to entering Atlanta had been overcome. Alarmed at the imminent danger posed to the city of Atlanta, and frustrated with the strategy of continual withdrawals, Confederate President Jefferson Davis relieved Johnston of command on July 17, replacing him with the aggressive John Bell Hood, who was temporarily promoted to full general. Hood proceeded to attack Sherman in battles at Peachtree Creek, Atlanta/Decatur, and Ezra Church, in all of which he suffered enormous casualties without tactical advantage. Sherman besieged Atlanta for the month of August, but sent almost his entire force swinging to the south to cut off the city's last remaining railroad connection. In the Battle of Jonesboro, Hood attacked again to save his railroad, but was unsuccessful and was forced to evacuate Atlanta. Sherman's men entered the city on September 2 and Sherman telegraphed President Lincoln, "Atlanta is ours, and fairly won." This milestone was arguably one of the key factors enabling Lincoln's reelection in November.