By July 1863, the American Civil War had entered its third brutal summer. In the East, Confederate forces under Robert E. Lee had turned back repeated Union attempts to capture Richmond, carried the war northward to Antietam Creek in Maryland, and then advanced into Pennsylvania, where the three-day battle at Gettysburg ended in a decisive Confederate loss. In the West, Union armies had repulsed a surprise Confederate attack at Shiloh, stopped Braxton Bragg's Kentucky invasion at Perryville, gained control of almost all of the Mississippi River, and brought Vicksburg to the verge of surrender under General Ulysses S. Grant, while General William Rosecrans drove Bragg back toward Chattanooga in middle Tennessee. Seeking a bold response that would lessen Northern support for reinforcing Rosecrans, Bragg turned to Brigadier General John Hunt Morgan, a daring Confederate cavalry commander known as the Thunderbolt of the Confederacy, and directed him to ride through the interior of Kentucky disrupting Union activity. Morgan chose to go beyond those orders, crossing the Ohio at Brandenburg, Kentucky, on July 8, 1863, and after six days of raiding through southern Indiana, crossing the Whitewater River at Harrison on July 13 before the pursuit continued into Ohio, where he was captured on July 26.