Antique Sterling Silver Dinner Plates - Possibly Quite Old

I have some beautiful sterling silver dinner plates that I believe are quite old and possible quite valuable. I was hoping that someone could help to identify their origin and perhaps give me an idea of their value.

I have 3 pictures to share. One shows the full plate, another shows a close-up of the detail and another shows a close-up of the hallmarks from the bottom of the plate. They are just a bit more than 9 inches in diameter and each weighs about 540 grams (1 lb. 3 oz.)

Feel free to contact me at likewho@aol.com if you need more information.
THANK YOU FOR ANY HELP YOU CAN PROVIDE
Dinner Plate.JPG
Dinner Plate Closeup.JPG
Dinner Plate Hallmarks.JPG