Mysterious Umarked Copper/Tin Decorative Plate with Detailed Mythological Imagery

I am trying to figure out anything I can about this decorative plate.  I am assuming it was made in the U.S. (I got it in New York) but it does not appear to have a maker's mark anywhere.  The plate is 11.5 inches in diameter and it weighs approximately 21 ounces (600 grams).

Does anyone know the specific name for this kind of plate, its time period, its place of origin, the group of people who made works of this kind, the name of this style of imagery, or any other details?

Thank you!