This looks like a (miniature) roman legionarie's shield or scutum, but with a much more complex decoration, with many more lightning bolts than on regular Legions' shields.
The more elaborate pattern make's me think maybe it's supposed to be a Gladiator's shield from a statue maybe?
Not antique of course a more "modern" repro but old nontheless...
It seems to be some sort of shoulder epaulette judging by the type of fasteners on the back. Designed to slip over the cloth shoulder strap on a uniform. I'm just not having any luck finding the design any where.