If you're looking for fantasy, I can give you a lot.
If it's just medieval then the closest I can get to is this:
Davie Gemmell's last work was the Troy trilogy. Really good set of 3 books - telling the tale of troy, obv, and there's some excellent characters in there. I believe Gemmell died whilst writing the 3rd book, and his wife finished it off.
Legend, also by Gemmell is a story about an old hero and his last battle (fought defending a multi-walled castle).
Also try Daughter of the Empire by Raymond E Feist and Janny Worts (i think?) if you like a book with lots of politics and back story.
I actually read that Feist/Worts trilogy before I read Magician and I guess I had a unique outlook when I finally read Magician as I knew a lot about those invading "aliens" having read Daughter of the Empire and the other 2 books countless times.
There's little to no magic in any of these books. Daughter of the empire has "Great ones" but you dont really see them much. It's more about the politics of the clans and Mara's fight just to survive (the heroine). Legend has none that I can think of, and Troy has no magic either.