I thought I had posted this here years ago but can't find it. So, trying again... raining here so had to use electric lights. Will try and get some better shots in the am.

Your piece appears to be a 15th/16th C. round bronze plaquette, probably made by Moderno (Galeazzo Mondella Italian, 1467 - 1528) and is depicting St. Jerome in the desert. I hope this helps?