of Mobile, Alabama. He remained there until late April 1863, when he was ordered to take command of the Army of East Tennessee. He arrived in Knoxville on May 11, 1863, and assumed command the following day. Shortly thereafter, his department was converted into a district of the Department of Tennessee under Gen. Bragg and was designated the Third Corps of the Army of Tennessee. In late August, Union Maj. Gen. Ambrose Burnside approached Buckner's position at Knoxville. Buckner called for reinforcements from Bragg at Chattanooga, but Bragg was being threatened by forces under Maj. Gen. William Rosecrans and could not spare any of his men. Bragg ordered Buckner to fall back to the Hiwassee River. From there, Buckner's unit traveled to Bragg's supply base at Ringgold, Georgia, then on to Lafayette and Chickamauga. Bragg was also forced from Chattanooga and joined Buckner at Chickamauga. On September 19 and 20, the Confederate forces attacked and emerged victorious at the Battle of Chickamauga. Buckner's Corps fought on the Confederate left both days, the second under the "wing" command of Lt. Gen. James Longstreet, participating in the great breakthrough of the Union line. After Chickamauga, Rosecrans and his Army of the Cumberland retreated to fortified Chattanooga. Bragg held an ineffective siege against Chattanooga, but refused to take any further action as the Union forces there were reinforced by Ulysses S. Grant and reopened a tenuous supply line. Many of Bragg's subordinates, including Buckner, advocated that Bragg be relieved of command. Thomas L. Connelly, historian of the Army of Tennessee, believes that Buckner was the author of the anti-Bragg letter sent by the generals to President Jefferson Davis. Bragg retaliated by reducing Buckner to division command and abolishing the Department of East Tennessee. Buckner was given a medical leave of absence following Chickamauga, returning to Virginia, where he engaged in routine work while recovering his strength. His division was sent without him to support Longstreet in the Knoxville Campaign, while the remainder of Bragg's army was defeated in the Chattanooga Campaign. Buckner served on the court martial of Maj. Gen. Lafayette McLaws after that subordinate of Longstreet's was charged with poor performance at Knoxville. Buckner was briefly given command of Maj. Gen. John Bell Hood's division in February 1864, and on March 8, he was given command of the reestablished Department of East Tennessee. The department was a shell of its former self—less