This wasn't a literary tour de force for me but it did something much more interesting than most YA historical fiction for me which was to present a very fraught situation (the late 13th-century English annexation of Wales) without sparing any of the brutally disproportionate misery or the terrible consequences or the rotten character of its English protagonist, but also without promoting moral simplicity. It started out in the classic "terrible privileged teen learns compassion" mode but developed more subtly than that. New history to me, also.