Long story short, and this should give you all the names you need to make Google sit up and fetch.
Start with a bunch of bored Victorian lodge members, such as Aleister Crowley and Arthur Waite, who had fun cursing each other. Another of them was a guy named Gerald Gardner, who decided it would be much more fun to hang out with naked chicks, so he announced that his grandmother was a witch who had "initiated" him while he was quite young. And he went on to explain at GREAT length how witchcraft was really the Old Religion of the Goddess and (amazingly) just happened to have all these rituals that are remarkably similar to those of his old lodge. (Heh.)
He had a nice deal going through the forties and fifties where his initiates would initiate people, and it was a big deal to be a certified Gardnerian in the sixties. But after a while the people who couldn't get initiated in a direct line of descent from one of his initiates decided that hey, they had grandmothers, too.
Hey Lestat -- you run into any guys who were into Asatru?