Got this today, but I think it was misattributed. Description was "Papal states, Innocent X, 1644-55, Silver Giulio" But it seems too big for a Giulio. Weighs 9.32 g, ~29 mm diameter I think the obverse says: "P.MAX.A.XI PAVLVS.V." Reverse: "S.PAVLVS. .ALMA.ROMA" From the weight I'm thinking maybe a testone of year XI = 1615. But I haven't been able to find a good match of the reverse in Krause or on Numista. To me it looks like St. Paul standing with a book on the left and a sword on the right. Any advice would be much appreciated!
I agree the size seems a bit big. If I had to guess, your coin is probably a Testone. Here is a Giulio of Paul V for comparison. https://en.numista.com/catalogue/pieces113623.html