Start with high-confidence medieval ya books, then narrow by subgenre or adjacent topics.
Black Horses for the King
Anne McCaffrey
A Daring Sacrifice
Jody Hedlund, Hayley Cresswell
The Girl in the Castle
James Patterson, Emily Raymond
The Shining Company
Rosemary Sutcliff
The King's Shadow
Elizabeth Alder
The Door in the Wall
Marguerite de Angeli
Anna of Byzantium
Tracy Barrett
Dauntless
Dina L. Sleiman
Courageous
The Silent Songbird
Melanie Dickerson
Fortress of Snow
Cloak of Scarlet
Lady of Disguise
Court of Swans
Melanie Dickerson, Jude Mason
Travelers Along the Way: a Robin Hood Remix
Aminah Mae Safi
Mortal Heart
Robin LaFevers
Martyr's Fire
Sigmund Brouwer
The Noble Servant
The Piper's Pursuit
Daughter of Doom
Jean-Claude van Rijckeghem
The Circle Cast
Alex Epstein
