 What have you changed your mind about recently?
pg: The late Roman empire, thanks to Theodosius: The Empire at Bay:http://www.abebooks.com/servlet/SearchResults?bi=0&bx=of...I used to have very unclear picture of the late empire.  Without thinking about it too much, I bought into the pervasive idea (probably due mostly to Gibbon) that the late empire had lost its Roman mojo: that it had become barbarized (what does that mean?) and worn out (why then?).  Now I have a higher opinion of the late empire. They lost largely because they faced harder problems.  The empire was depopulated, partly no doubt due to epidemics, and the barbarians on the frontiers were a greater threat than they had been in the time of Augustus.I'm only half way through the book, but it's already the best thing I've read on the period.  It would be worth reading for their revisionist view of Adrianople alone.