Help me find a book title.

Ok now that the OG fixed itself....





So my father inlaw swears he read a book when he was in the Romanian Military about a Pope that had an illegitimate son who becomes a pirate. Says it's the best book he ever read. I have looked for about 5 years, never finding anything.....



So I have come to the OG saviors

holy shit don't know but please post if you find out

don't know if this will help:

Sounds like the plot for Pirates of the Caribbean 6