Why do you write "European", is there a story for this mug?
I think this could be German (maybe Bavarian by only one man's clothes and hat) but on the other hand I can't be sure, could be Austrian aswell...
DK I think is the marking but could not locate a German maker.
If it is German you could further search under "Steingut" or "Steinzeug Bierkrug". Do you think your mug may lack a originally attached pewter lid?
There is every chance it's simply an art pottery mug with the student's/maker's initials. I suggest you take it to a dealer who can actually see it, touch it and evaluate it. It is a nice looking mug, but a pro will be able to tell you almost immediately if it's antique.