That was my question, too. I really don't think it's a pendant from a necklace....too big and heavy, so the hole wouldn't be for that. I thought if it was an escutcheon, maybe that hole was for a nail for added security. But AARC made a good point....if it is an escutcheon, the back probably wouldn't look like the front (which it does.) And I know nothing about horse rosettes except for what I googled. I didn't find that they would have a hole in the middle. So I think the mystery remains. Thanks for your input.