It was alright. Philippa Gregory certainly has written better - the witchcraft was portrayed much more successfully (i.e. entertainingly creepy) in The Wise Woman, for example. There were some war scenes in there which I suppose were meant to be moving but failed in that regard. Also, the Melusina sea goddess motif got annoying, fast. 
 The second book in this trilogy, The Red Queen, was a little better. 
 The security guy at Heathrow made fun of me for having this book in my backpack. What? Should I have been reading For Whom the Bell Tolls or something? Asshole.