This large, solid hammered copper Pommern tray measures 19.25" across at widest part (corner to corner) and weighs about 2 pounds 12 ounces. It has a good patina on it but could be polished up if so desired. There is a slight dent to top right corner but this should be easily fixed since it is hammered copper anyway.
Pommern is the German word for the Province of Pomerania, which was a province of Prussia before World War 2. It was dissolved after WW2 and divided between Poland and Allied-occupied Germany.
The tray appears to be hand-made. It displays Pommern and a somewhat crude depiction of its Coat of Arms, which is very similar to that of Poland. I don't have any information specific to the tray other than measurements and photos. I don't see any markings to identify it. I would assume it's at least pre-war because I'm not sure why it would be made after. If it was made after, I believe it would more likely be made in Poland and use the Polish term Pomorze.