Complex sentence: He enlisted in the regular army, January 2,1864 during the Civil War, and was assigned to the 16th Infantry; was promoted corporal and served as commissary and quartermaster-sergeant until May 21,1865.
Split into simpler sentences: He enlisted in the regular army on January 2,1864, during the Civil War, and was assigned to the 16th Infantry. He was promoted corporal and served as commissary and quartermaster-sergeant until May 21,1865.