To expand the question, how did a Roman citizens idea of "Roman-ness" differ from a 19th century Frenchman's idea of "Frenchness"?
http://www.reddit.com/r/AskHistorians/comments/2jlr4e/nationalism_as_we_know_it_didnt_exist_in/cld13if
Take a look at this post and see if it helps. Any further questions just ask! :)