Vampires and Invitation into Private Dwellings
After the latest episode of Vampire Diaries last night, it got me thinking about the law of invitation for vampires. This law is not used in every vampire myth and story, lately it was used in Let The Right One In, along with movies such as movies Fright Night and The Lost Boys. Also this was a plot device on TV shows such as Buffy and Angel, and recently in True Blood
From my knowledge, older stories such as Dracula and Carmilla didn't entertain this rule, and I wonder where it came from, and also which writers/filmakers were the first to use it in their stories?
In Dracula, there is some kind of mirrored law with invitation where Harker must "Enter Freely Of His Own Will" into Dracula's Castle though this could be a magical solution or trick to breaking the will of Harker, and dominating him as the Castle belonged to Dracula.
The first novel that I found to have an invitation revoked was Stephen King's Salem's Lot, while some other popular vampire series such as Rice's The Vampire Chronicles don't use this law at all, and from most of the modern vampire literature I've read over the years, this law seems to be as sparsely used as a vampire's reflection in mirrors.
So I'll put it out to my readers to test their knowledge. What do you know of The Law of Invitation, and what it's origins were, and what do you think of it as a plot device?