I regularly read stories about the Gods of ancient Greece, Rome, Egypt, etc. Even if we wind the clock forward, we see huge battles such as the Crusades fought in the name of religion. The concept of a God is something which has dominated our history in so many ways. However, as a casual observer, I have never come across atheism throughout history - it seems to be a fairly modern idea.

Were there people in ancient Rome, Greece etc where they simply said they do not believe in Gods? If so, how were they treated? How common was this? Did the masses genuinely believe that it was the Gods who brought the sun up each day?