Being assigned, elected or promoted a first sergeant may indicate prior military experience, but more likely it demonstrates someone who held the respect of the men under him in some prior capacity and has the ability to keep order, assign work and maintain discipline. He may have been a shop Stewart, or some type of work "boss" before enlisting. A first sergeant must be able to read and write because they are responsible for daily reports, organizing work details through sergeants and corporals under them and setting a good example for the men. Best Regards, Rick Frederick E. Walton Civil War historian