With that Fragonard style plaque on the cover, one might have expected to open it and discover a music box.
Maybe it's multifunctional - perfume bottles and creams, or ink bottles and writing accessories...keepi ng those love letters safe. There does appear to be an ink stain on the base so it was probably on someone's desk at some point.
Maybe have been an internal compartment which has been removed when someone decided to use it for something else.
Bible box seems unlikely although that's not to say you couldn't keep a bible in there !