There must have been a moment at the beginning, where we could have said no. Somehow we missed it. Well, we'll know better next time.
We went to Pandora and typed in "Gregorian Chant". That gave us great background music for the game.
I have a Pandora channel that I seeded with Benedictine Monks Of Santo Domingo De Silos (and nothing else) that I use for music while I work, and the tracks they play on that channel would be perfect.