I am reading the Gemma Doyle triliogy. The first book is A Great And Terrible Beauty
the second is Rebel Angels
and the third is The Sweet Far Thing
I am currently reading the third book. It is an excellent series. It's based on the only myth's of a female 'Order' who all control the 'Realms' to make sure nothing escaped from one Realm to the Earth. The women involved are Preitesses. It is quite interesting. I love it so. I beleive it's a pegan myth, I do know I had heard of it before I read the books.
Don't worry, it is a Pegan myth, but the book isn't like, "Then we worship the trees" or anything. xD