[eksith]

Your best bet would be to ask them directly.

I don't know how they could claim copyright on the original works, but they may have a case if you reuse their digitized copy of the original work. Much like a photograph of a piece of art may fall under a different copyright (that of the photographer) vs. the art itself. Also, the Vatican operates under a different set of rules than the rest of Italy, so I don't know if Italian copyright laws apply the same there.