Other themes might include History, with historical fiction alongside actual history. Both provide an important look into the time and place, with historical fiction sometimes telling us more about the people and culture than pure history.
Or, radical thought, how about including alternative history? For example, I know FAR more than I ever thought I would about the 30 Years War and mid-17th century Europe based on having read Eric Flint's 1632 series. Oh, and they were a lot of fun.
