I'm sure king Aurthur was a half blood. I have my guesses about who his godly father was . . .

and really Olympus must have been over that area for sometime. Really, you're looking for labyrinth entrances and and and didn't Lady G spring from the head of her father???? (ok, maybe not)

I can help you think of justifications to bring the book anywhere (I convinced Len that it was ok to read our friend's copy of the fourth book while in the swimming pool.)