I'm a morning person because I learned to write my novels while still practicing law. I would get to the office at 6:30 a.m. and write until other people arrived around 9. Now I still do that. I start at 6:30 or 7 and I'll write until 11 then take an hour off then work until about 2 p.m. By then my brain has had enough.
In every age there has been a stream of popular opinion that has carried all before it and given a family character as it were to the century.