I discovered that one of my ancestors served in the Civil War. His name was Louis F Romagosa, he was a private with the Consolidated 18th Regiment and Yellow Jacket Battalion. I'm taking course on the Civil War and working on a project. I found where he was a POW but released on June 6, 1965 in Natchitoches. I'm trying to figure out what battle he fought in and if he received a pension but I don't think I'm researching in all the right places. Any guidance would be appreciated. Also, what does C.S.A. stand for? Thanks!