Here is another picture, gives more detail of the shape.
So here is what we know about it:
* It depicts St. George and the Dragon
* Its either made from pewter, spelter, or silver, (it kind of looks like lead)
* The plate is small, much of the size of a tipping plate.
* The style is similar to French Antique Punched Work
* The french translates as: "Offered by the court St Georges of Ghent"
I will try and upload more pictures, don't have the plate right now with me.