Ten unknown truths about sacred music
Jeffrey Tucker has a great post Ten unknown truths about sacred music. My two favourites:
Cognitive pedagogy is not the primary purpose of music, so, no, it is not important that all people gathered always and immediately "understand the words."
The first piece of papal legislation concerning music appeared in 95AD, by Pope St. Clement. It forbid profane music in liturgy and emphasized that Church is the place for holy music. All successive legislation has been a variation on that theme.