My g-g-great grandfather's younger brother, Jonathan H. Estep served with the 13th KY Cav. CSA at the start of the war, was captured and sent to Camp Morton in Indiana. Upon exchange, he signed the Oath of Allegiance and then enlisted in the 45th KY Inf. USA as a Sergeant in 1863.
On his pension application he lists "confined at Camp Morton" as the cause of his infirmity requiring a pension. I find it rather ironic that he requested a Union pension for infirmities recieved while a Confederate POW.