Chattanooga constituted a critical rail rub whose lines radiated to the south. Following his defeat at Chickamauga, Maj. Gen. William S. Rosecrans and the Army of the Cumberland retreated to Chattanooga. Gen. Braxton Bragg's Army of Tennessee followed and laid siege to the city. With fortunes in the Western Theater teetering, President Abraham Lincoln dispatched Maj. Gen. Ulysses S. Grant to Chattanooga. Grant directed operations that ultimately lifted the siege and paved the way for Maj. Gen. William T. Sherman's Atlanta Campaign in the spring of 1864.