Old Ring with Makers Mark only - Need help identifing

[hootiegooter]

I just inherited a beautiful gold wedding band that I would like to know more about. I was told that it belonged to my Aunt's, Grandmother-in-law from Germany.
The only markings on it are 3 letters...XXM with the M being side ways. There are no other markings at all.
Can anyone tell me anything about the markings?
Thanks,
Nikki
.