Union soldiers hated and feared Libby Prison at Richmond, Virginia, more than any Confederate prison camp except Andersonville. Libby had been improvised from a commandeered tobacco warehouse in order to hold the officers captured in the First Battle of Bull Run in 1861 and had never been adequately provisioned. By the beginning of 1864 dwindling rations and the breakdown of prisoner exchange made life unbearable for the prisoners of a Confederacy that could barely feed its own population. Libby was dangerously overcrowded and underfed when, on February 9, Col. Thomas E. Rose led 108 other Union prisoners in the largest escape of the Civil War.