Popular music tends to have more rythym and upbeat,whil traditional music is more calming and low.
Answer:
Well, I don't have an answer but I need points (asking for a friend)
I believe because it was for the Christian persecution that took place around A.D. 64, since a lot of Christians did not want to give up their faith, but did not want to be killed, they hid every Christian symbol (I guess this could be the right answer, hope I could help!)
