In 1864, the Union Army moved southward following the capture of Chattanooga and began its invasion of north Georgia. The region surrounding Atlanta was the location of several major army battles, culminating with the Battle of Atlanta and a four-month-long siege of the city by the Union Army under the command of General William Tecumseh Sherman. On September 1, 1864, Confederate General John Bell Hood decided to retreat from Atlanta, and he ordered the destruction of all public buildings and possible assets that could be of use to the Union Army. On the next day, Mayor James Calhoun surrendered Atlanta to the Union Army, and on September 7, Sherman ordered the city's civilian population to evacuate. On November 11, 1864, Sherman prepared for the Union Army's March to the Sea by ordering the destruction of Atlanta's remaining military assets.