The word photography comes from the Greek "photos", meaning light, and "graphos" meaning drawing, but the ancient Greeks didn't invent photography. The word camera comes from the Latin "camera", meaning room, and "obscura", meaning dark. It's not surprising the Ancient Greeks didn't invent photography, after all, they never liked to get their hands dirty, but the Romans, who would have been at home in the "Dark Room", could have invented photography, but never did. Why?
Nowadays, most people take photographs. Remove the modern cameras and film, and many homes still contain the things needed to produce a photograph, things which the Romans could have had access to as well.
Read more how to do it step by step here: http://www.grand-illusions.com/roman.htm