W N Mercer was the adjutant of the 13th Arkansas Infantry. The regiment was formed Jul 29, 1861 in Greene County, Arkansas. Here's a short history:

Enlisted at Harrisburg, and organized for one year's state service at Gainesville on June 29, 1861 under the command of Colonel (later Brigadier General) James F. Tappan., and transferred to Confederate service on July 17, 1861 at Pocahontas. Field Officers were Lt. Col. A.R. Brown and Major Robert A. Duncan. Moved through Pittman's Ferry to Kentucky where Hardee's Division became the Army of Central Kentucky. Assigned to Travis' Brigade, Pillow's Division, where it fought it the battle of Belmont, MO on November 7, 1861. Col Tappan was promoted to the brigade command in March, 1862, and led it in the Battle of Shiloh on Apr. 6-7 and in the Corinth Campaign from April through June of that year. Company K of the 7th Kentucky Infantry was assigned to the regiment as a second "Company E" on April 13, 1862. The regiment re-enlisted and reorganized for a period of two years or the duration of the War on April 29, 1862. Following the evacuation of Corinth, moved to Tupelo, MS, and thence to Chattanooga, TN under General Bragg for his 1862 Kentucky campaign. Participated in battles of Richmond (August 29-30) and Perryville, KY on October 8, 1862. In December, 1862, reassigned to Cleburne's Brigade (later Liddell's Arkansas Brigade of Cleburne's Division) where it fought in the battles of Stones River (Dec. 31, 1862-Jan 3, 1863), Tullahoma Campaign in June, 1863; Liberty Gap (June 24-26, 1863), Chickamauga (Sep 19-20, 1863); Siege of Chattanooga (Sep.-Nov. 1863); Battle of Chattanooga, Ringgold Gap, Dalton, Resaca, the Atlanta Campaign, New Hope Church, Kennesaw Mountain, Atlanta, and the siege of Atlanta. Consolidated with the 15th Arkansas Infantry early in 1863, and additionally with the 5th Arkansas Infantry in August, 1863. Regiment and colors were captured at Jonesboro, Georgia on Sept. 1, 1864, and exchanged approximately 1 month later. Rejoined Cleburne's Division for Hood's Tennessee Campaign where it fought at Spring Hill, Franklin, and Nashville. Engaged in the Carolinas Campaign in early 1865, and at the last battle of the Army of Tennessee at Bentonville on March 19-21, 1865. Survivors were consolidated along with those of the 1st, 2nd, 5th, 6th, 7th, 8th, 15th, 19th (Dawson's) and 24th Arkansas Infantry and the 3rd Confederate Regiment (formerly Marmaduke's 18th Arkansas Infantry) to form the 1st Infantry Regiment (Consolidated) at Smithfield, NC on April 9th, 1865. Surrendered two weeks later with LTG Joe Johnston's Army of Tennessee near Durham, North Carolina.

Officers: Colonel (later Brigadier General) James C. Tappan. Field Officers: Lt. Col. A.R. Brown, Maj. (later Lt. Col.) Robert A. Duncan, Lt. Col. A.D. Grayson, Maj. E.A. Howell, Maj. George B. Hunt, Maj. (later Lt. Col.) James A. McNeely, and Lt. Col. James A. Pollard.