Well, well, well ...
If you don't know the name, then let me just assure you that Dario Argento's generally means that the produced vision is something minimally worth checking out. While I've not seen this one, I suspect that's the case, too: it's probably a bit of a nightmare.
On this day in Italy all the way back in the year 1989, The Church enjoyed its big screen debut. Directed by Michele Soavi (another name prominent in the field of Italian Giallo), the script shows credited to Soavi alongside Dario Argento, Franco Ferrini, Lamberto Bava, Fabrizio Bava, Dardano Sacchetti, and M.R. James. (There's an indication on IMDB.com that perhaps all of this stems from an original story by James, but I've yet to confirm those details.) The cast includes such faces as Hugh Quarshie, Tomas Arana, Feodor Chaliapin Jr., Barbara Cupisti, Antonella Vitale, Giovanni Lombardo Radice, Asia Argento, Robert Caruso, and others. Here's the plot summary as provided by IMDB.com:
"An old Gothic cathedral built over a mass grave develops strange powers that trap a number of people inside with ghosts from a 12th Century massacre seeking to resurrect an ancient demon from the bowels of the Earth."