Sterling Silver Gravy Tray

Very unusual sterling piece. Possibly pre-1800's. The workmanship is not perfect, and it has unusual Hallmarks...the bottom is inscribed "1612"...the front has an image of a "nero" head with a strange body. Over that is a banner with the words "WILL GOD I SHALL". Above that are the Hallmarks, left to right... H ,circled (possibly another letter before the "H", rubbed off)... then the Lyon (making it Sterling) , then the Kings head (the duty hallmark?), then the letter "M" encircled, but I don't recognize the Font, to date it. The Nero Head and Banner are largely encircled, looking like the emblem was smelted into the piece, similar to the circle at the bottom of the inside of the tray(which I assume is how the stand was attached). The imperfection is in the underside of the handle