True? I really don't know but I hope this helps
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!)
This is one of the tips you may want to try (I hope this helps)
Answer: A line can describe, showing delineation or, when materialized, result in linear form and can become sculpture without tangible volume. ... Besides describing volume or space, lines can be used to only suggest movement.
Explanation: Your welcome!