asking questions in this thread. Apparently, I am not. In moving from one age to another, sometimes I get a popup, sometimes not. In my current game, I'm in the middle ages, and have researched all non-optional techs. (The ones without the little "slashed circle" are the non-optional, right?) But I'm still in the middle ages, and now researching optional ones. Why didn't I advance to the IA? Thanks in advance.