Barbara Tuchman's "A Distant Mirror" is supposed to be about the politics of France, Britain, and western Europe circa the 1350s, but she goes into substantial background detail.
The entire era was driven by two things - "global cooling", which ruined agriculture when they got snow instead of a second growing season, and the Black Death. Pretty well destroyed the established political and social order.
It's a "scholarly" work, and I found it hard to work up much interest in the book's main subject, but she did a very good job of giving the background on *why* things happened the way they did after climate change and plague kicked everything over.
I read her "Guns of August" book, and have learned much more than I ever did about WW1. Interesting to hear about her others. Love the medieval stuff.