It describes an era, Spain after the Reconquista, that is not well known to me, so interesting from that standpoint.
This book tries to be 2 things though, a history book and a novel. I think it would have improved the book if it was focused on one of those things.
The protagonist is a bit too much of a do-gooder to be interesting or even believable. I also thought the dialogue could be a bit snappier.
Still, I finished it, so it was OK.