the war. A few days after the fall of Chattanooga, Confederates led by James Longstreet unsuccessfully campaigned to take control of Knoxville by attacking Union General Ambrose Burnside's Fort Sanders. The capture of Chattanooga allowed Sherman to launch the Atlanta campaign from the city in May 1864. The last major battles in the state came when Army of Tennessee regiments under John Bell Hood invaded Middle Tennessee in the fall of 1864 in an effort to draw Sherman back. They were checked by John Schofield at Franklin in November and completely dispersed by George Thomas at Nashville in December. On April 27, 1865, the worst maritime disaster in American history occurred when the Sultana steamboat, which was transporting freed Union prisoners, exploded in the Mississippi River north of Memphis, killing 1,168 people. When the Emancipation Proclamation was announced, Tennessee was largely held by Union forces and thus not among the states enumerated, so it freed no slaves there. Andrew Johnson declared all slaves in Tennessee free on October 24, 1864. On February 22, 1865, the legislature approved an amendment to the state constitution prohibiting slavery, which was approved by voters the following month, making Tennessee the only Southern state to abolish slavery. Tennessee ratified the Thirteenth Amendment, which outlawed slavery in every state, on April 7, 1865, and the Fourteenth Amendment, which granted citizenship and equal protection under the law to former slaves, on July 18, 1866. Johnson became vice president when Lincoln was reelected, and president after Lincoln's assassination in May 1865. On July 24, 1866, Tennessee became the first Confederate state to have its elected members readmitted to Congress. Reconstruction and late 19th century The years after the Civil War were characterized by tension and unrest between blacks and former Confederates, the worst of which occurred in Memphis in 1866. Because Tennessee had ratified the Fourteenth Amendment before its readmission to the Union, it was the only former secessionist state that did not have a military governor during Reconstruction. The Radical Republicans seized control of the state government toward the end of the war, and appointed William G. "Parson" Brownlow governor. Under Brownlow's administration from 1865 to 1869, the legislature allowed African American men to vote, disenfranchised former Confederates, and took action against the Ku Klux Klan, which was founded in December 1865 in Pulaski as a vigilante group to advance former Confederates' interests. In 1870, Southern Democrats