Medieval European History is one of the times most trampled (though I think the Regency/Napoleonic is fast catching up) anent the recent discussions about Hollywood backdrop history in fiction. Though yes, many readers want exactly that--the superficial trappings of the past, with characters who have mostly modern outlooks. And it's not just in our genre--Ken Follet really disappointed me with his medieval books, much as I liked Eye of the Needle.
Anyway, one of the writers
who does know medieval times is Judith Tarr, and one of her most popular medieval historical fantasy romances is
The Dagger and the Cross--now available as an e-book.