I heard a lot of catholic mass songs in my life, but not one that has an opening like this. Can you tell me if the song above is an homage to an actual church song?
He's using a few short phrases of text from Latin prayers as part of the refrain, and some other references to religion; but I don't think the melody comes from any church songs.
Try watching silent films that are shown to the public with organ improvisational accompaniment. Organists are trained to make music up - they were improvising before jazz musicians were. That's the "type of ... music like this." Not a coincidence at all.
It seems to be a pop song with some religious themes, which wasn't unusual in 1968. In American pop music, we can think of songs like "Spirit in the Sky", or "Are You Ready?", or hit songs from religious-themed musical plays such as "Godspell" or "Jesus Christ Superstar". http://www.rebeatmag.com/the-early-1970s-when-jesus-rock-ruled-the-airwaves/
The Latin words of the refrain do come from Catholic sources:
"Miserere nobis" (have mercy on us): words addressed to Christ in every Mass: "Lamb of God, you take away the sins of the world: have mercy on us".
"Ora pro nobis" (pray for us): words addressed to the Virgin Mary during the recitation of the rosary, in the prayer "Hail Mary": "pray for us sinners now and at the hour of our death".
In the video-game music? Yes: I suppose that sort of ornament is typical of baroque harpsichord works, hm? The composer, Motoaki Takenouchi, produced music for numerous video games, and since he studied music at university, it is not surprising that he would be acquainted with historical styles of instrumental music.
Despite the religious-sounding title of the video-game music, the style is like instrumental music written for home entertainment; it does not sound like any famous piece of religious music.
To participate in the discussions on Catholic church music, sign in or register as a forum member, The forum is a project of the Church Music Association of America.