My gggreat grandfather, John Holland, enlisted in Co. H, 3rd MSM in 1862. This regiment later merged (?) with the 7th MSM Cavalry, and John was assigned to Company L. How can I find out the battles in which John participated. He was 51 years old, and I don't know if he would have participated, but it would be interesting to find out. Also, where would I find out if there were photos taken of John or the Regiments he was in.