What are some comps to The Historian (but not vampire comps)

I’m not necessarily looking for comps in terms of other books related to Dracula or Vampire. I’m more looking for books that follow the same formula of having a scholarly protagonist wrapped up in a thriller or solving a historic mystery. Specifically in that Late 19th century to early 20th century European travels type of setting. Essentially a Dan Brown novel wrapped in pre-war colonial influenced European travels.

I’ve made a similar post before, but if anyone can also help with more industry specific terms that may already be established that better describe some of the things I’m asking for, those are much appreciated.