I noticed this comment here that give you insight of medieval people in perspective like "great powers" idea of politics, political cynicism and similar. Hope it helpful (it also a good war strategy-economy-politic fanfic, btw)
https://forum.questionablequesting.com/threads/focused-fire-atla.20925/page-249#post-7465103
https://forum.questionablequesting.com/threads/focused-fire-atla.20925/page-249#post-7465103