I
think I remember the Stalags, at least in WWII, being numbered using Roman Numeral - such as
'XI/I.
In WWI, the
XI Army Corps (Cassel) had three camps, one for officers and the other two of which held 25,000 enlisted men.
I wonder if the badge indicates camp:
XI/I , compound or division or some such:
5 / 3, and prisoner number:
289?
https://en.wikipedia.org/wiki/List_o...r-of-war_camps)