The main thing that we should unlearn is this "retro-racism," in a sense that we treat these people almost as apes instead of modern human beings, basically our biological peers, capable of the same feats as we are. I mean, we still treat medieval people as incredibly stupid and dull. Once you let go of that, it becomes much more exciting to look at the history because it allows for more interesting possibilities. This is the basic premise behind "The Dawn of Everything" which I am reading at the moment. Very good book, I recommend it.