Every guess I made and googled linked straight back to the original photo.
Here is something interesting about the photo.
I think the last letter is actually a N and possibly the other letter that people think is an R.
M. G. Nildian
Sometimes we have to be really creative in spelling or misspelling.
But looking at it just now again, I was thinking. we must assume, we have a First initial and a last name.
Because why would the First and middle initial be capitalized but not the first initial of the last name. That doesn't make sense.
So the first letter is the First initial of the first name.
Probably an M.
The rest of it is all the last name. There is just a bit of a space between the first and second letters of the last name.
My guess is that the first letter of the last name is either a S or an G.
I also have my great great grandmother’s https://www.wikitree.com/wiki/Ronger-1 first husband Samuel Grant Profile here https://www.wikitree.com/wiki/Grant-5394 who died in the civil war with a special photo from our Simpier family album. We had a hard time with it also, but found the name on the back wasn’t of Samuel Grant Which makes the mystery more interesting but found the name on back of this picture to be of Curtis S. Dye https://www.findagrave.com/memorial/110089365/curtis-s-dye my question is this how did my simpier family album get this photo in it? My great great grandma Matilda Ronger (Grant) Simpier remarried Joseph Simpier who served in the civil war also. So maybe it’s Samuel Grant or maybe Curtis. Maybe they were friends. Unsolved mystery
So I checked find a grave listings which helped. Also the other info like uniform and any insignias showing rank etc any more clues from photo other than the writing on back
I also can’t find Captain Curtis S. Dye on wikitree yet