Resaca set the tone for the first phase of the campaign, as Sherman's armies attempted to maneuver around Johnston, and Johnston continually fell back toward Atlanta. On June 27, Sherman departed from character and attempted a direct assault on Johnston's position at Kennesaw Mountain. When that failed, Sherman swung McPherson from the left around to the right in order to resume his southward progress. On July 18, as the Army of the Tennessee completed a giant wheeling maneuver from Sherman's right to his left and cut the Georgia Railroad east of Decatur, John Bell Hood replaced Johnston as the Confederate commander. The aggressive Hood soon initiated the Battle of Peachtree Creek (July 20); his attack was intended to exploit a gap in the Union lines (between Thomas on the right and Schofield in the center) but ended unsuccessfully. Then, in the Battle of Atlanta on July 22, Hood launched a strong assault against McPherson's army, on Sherman's left. McPherson himself was killed, and command temporarily passed to Maj. Gen. Logan, his senior corps commander. The July 22 battle, writes one historian, was "the climax of the Army of the Tennessee's wartime career," as 27,000 men "defeated the attacks of nearly 40,000 Confederates who had the advantages of surprise and position."