Oh, good! In Our Time is one of my old reliables - I listen to most episodes even if it's a topic I'm not interested in because hearing passionate academics getting herded around by the host is interesting (and sometimes very funny). Lots of mumbly British accents that I sometimes struggle with, but I also love the high percentage of women in academia that come on for the panel.

Tides of History used to be a podcast specifically about the circumstances around the long fall of the Roman Empire, and then the host concluded that and rolled into a more far-ranging history one. I enjoy it a lot as well.