Major Daniel W. Jones was promoted to colonel, and Captain Robertson succeeded him as major of the regiment. Following the Corinth Campaign, the regiment was reassigned to General Martin E. Green's brigade, in the Confederate Army of Mississippi, Department of Mississippi and East Louisiana. Part of Green's brigade, including many from the 20th Arkansas was captured and Major Robertson was killed in the Battle of Big Black in rear of Vicksburg on May 17, 1863. The remnants of the regiment fell back inside the works and endured the forty plus day Siege of Vicksburg. The prisoners from the 20th who were captured at Big Black were sent to prison camps in the north and eventually exchanged at City Point Virginia in December 1863. The remainder of the regiment surrendered with the Army of Mississippi at Vicksburg, Mississippi, on July 4, 1863. General U. S. Grant initially demanded the conditional surrender of the Vicksburg garrison, but faced with the necessity of feeding 30,000 starving Confederates and having the idea that these soldiers might do more harm to the Confederate cause by being released to return home rather than being exchanged as whole units, he relented and allowed for the immediate parole of the unit. According to the Confederate War Department, the Union leader encouraged the surrendered Confederates to simply return home, rather than being officially paroled and exchanged. The able bodied Confederate soldiers who were released on parole walked out of Vicksburg (they were not allowed to proceed in any military formations) on July 11, 1863. Paroling of these able bodied men was completed in their respective regimental camps inside Vicksburg prior to July 11. The soldiers of the 15th Northwest Arkansas were paroled on July 8 and 9, 1863. Those who were wounded or sick in the various hospitals in Vicksburg were paroled, and were released, as soon as they could leave on their own. July 15/16 is the most common date of these Vicksburg hospital paroles. Some of the most seriously wounded and sick were sent by steamship down the Mississippi River and over to Mobile, Alabama, where they were delivered on parole to Confederate authorities. Confederate commanders designated Enterprise, Mississippi as the rendezvous point (parole camp) for the Vicksburg parolees to report to after they got clear of the last Federal control point at Big Black Bridge. Most of the Arkansas units appeared to have bypassed the established