Shadows and Strongholds by Elizabeth Chadwick
An awkward misfit, nine-year-old Fulke FitzWarin leaves his family for the household of Joscelin de Dinan, Lord of Ludlow. Once there, he begins to learn the knightly arts which he desperately hopes will free him from the shadows of his past.
Joscelin's youngest daughter, Hawise, befriends Fulke when he most needs it. But as the years pass, an enemy to Ludlow changes their friendship unalterably, forcing them onto opposite sides of a cruel divide.
When the menace to Ludlow intensifies, Fulke must confront the future head on or fail on all counts, all the while desperate to know if Hawise stands with or against him.