I feel like I'll expand my thoughts a little more after having read some more opinions from here.
What it comes to is the question: Why?
Why do you feel like writing this much dialog is a problem? Is it because it just doesn't look like a novel you're used to? That would be enough to give anyone doubts, but that is not an answer. Ask yourself, what does the dialog do to my story? There are the basics to look at, such as does it advance the narrative, build character, and feel like a natural progression from what came before, but that's true of anything. The next level is to determine what this does stylistically. Dialog typically reads very fast. The words-to-action ratio is very high, so the scenes will feel like they're flying by. Especially on a tactile level, as all the new paragraphs will mean dialog takes a lot of page space, and the reader will be flipping pages faster than they're used to.
Are these things you want in your story? And why do you want them there? If this is not what you want your novel to read like, then it's time to rework your scenes. What are you conveying through dialog that you should convey through setting, gestures, or actions? (for example, if you have dialog akin to, "gosh, your so lazy so Sir Micheal," you could cut that and have a description of Micheal's unpolished armor, untended to horse, and a look from Sir John of disapproval).
However, if you're aware of what the dialog is doing to your story, you can try to make that your advantage. In this historical book, is it a time of chaos? Upheavel? Or the characters in a rush for some reason? Giving that heavy dialog speed could help the reader feel the rush of pace on a visceral level. But if the book is about a slow, relaxed time, maybe scenes told almost always through dialog don't suit the purpose?
When I say lean into it, that's what I mean. Heavy dialog itself isn't a sin. Unless it's used unthinkingly or inappropriately.