During Union Maj. Gen. William Tecumseh Sherman's Atlanta Campaign Wheeler's cavalry corps screened the flanks of the Army of Tennessee as Gen. Joseph E. Johnston drew back from several positions toward Atlanta. In July, Sherman sent two large cavalry columns to destroy the railroads supplying the defenders of Atlanta. With fewer than 5,000 cavalrymen, Wheeler defeated the enemy raids, resulting in the capture of one of the two commanding generals, Maj. Gen. George Stoneman (the highest ranking Union prisoner of war). In August, Wheeler's corps crossed the Chattahoochee River in an attempt to destroy the railroad Sherman was using to supply his force from Chattanooga. Wheeler's men captured the town of Dalton, but he was unable to defeat the Union garrison, which was protected in a nearby fort. Wheeler then took his men into East Tennessee, crossing the Tennessee River above Knoxville. His raid continued to the west, causing minor interruptions in the Nashville and Chattanooga Railroad and then continued south through Franklin until he recrossed the Tennessee at Tuscumbia. The raid Wheeler was ordered to undertake was described by historian Ed Bearss as a "Confederate disaster" because it caused minimal damage to the Union while denying Gen. John Bell Hood, now in command of the Army of Tennessee, the direct support of his cavalry arm. Without accurate intelligence of Sherman's dispositions, Hood was beaten at Jonesborough and forced to evacuate Atlanta. Wheeler rendezvoused with Hood's army in early October after destroying the railroad bridge at Resaca. That said, the blame for this defeat cannot be laid at Wheeler's feet.