Ed,
An unusual piece to be sure...
... most likely one-of-a-kind, unofficial or semi-official decoration for an office, good-sized club or organization - S�ngerbund, Sch�tzengild, Kriegerverein, perhaps a university or some government department, something along those lines. The reason I say unofficial is because I can't recall having ever seen this type of decoration in a book, photo or document. Real, original and authentic...? .. yes, no question, absolutely lovely.
I'd say the eagle isn't from the "royal-house" proper but is the well known state wappen-crest of Prussia. I have a heavy metal shield about the size of your decoration that's wonderfully enameled but nowhere near the fabulous design and construction of yours. Is the knurled piece at the top open to accept a chain of some kind? I'm wondering if that may have been the main method of wear at some time?
The catch is very interesting for me as this barrel-assembly is often associated with postwar items, which this is definitely not. Without actually having the piece to feel and study, I'd be hard-pressed to give a date of manufacture. My initial reaction is to say late 1900's but it might also be late Weimar/early TR too ..? I've seen more than a few non-military medals that look like thay were made in the early teens and were actually engraved on the reverse with the year 1938 or '39.
... sometimes a bit of a surprise!
I do want to thank you for sharing this wonderful find with us and I wish you all the best in finding more such treasures!
Kind regards!
Bill Warda
