The chapel portrays nothing less than the story of man, in three from Adam to Noah; the giving of the Law to Moses; and from the birth of Jesus to the Last Judgment.
The story portrayed in the chapel begins in Roman times. 
mnli hypothesis: The story portrayed in the chapel begins in Roman times.  premise: The chapel portrays nothing less than the story of man, in three from Adam to Noah; the giving of the Law to Moses; and from the birth of Jesus to the Last Judgment.