William Andrew Martin was mustered into service as second lieutenant of Co. I, 20th Arkansas Infantry, on February 26, 1862. He was promoted to first lieutenant on April 9, 1862. During the army-wide reorganization at Corinth, Mississippi, in May 1862, Lieutenant Martin was not reelected in the company elections held on May 13, 1862. It is unclear if he was defeated in the election, or simply declined to run for reelection -- I suspect the latter. Upon his return to civilian life, he was subject to the Conscription Act. So he enlisted (or was conscripted; again unclear) in Marshall's Battery on February 7, 1863.