Haven't read book six yet (I'm in the "Holds queue" at the local public library), but I have gathered quite a bit about what happens from reading various websites. I'm not trying to avoid "spoilers" - on the contrary, I am seeking them out!

One thought has come to me - all this business of the horcruxes reminds me of the "Key to Time" sequence in Doctor Who. I'm sure that someone could tell me that that was in turn taken from an older folklore, so perhaps JKR didn't lift it from Who.

Don