A thought that occurred to me a while ago: who came up with the first Knock-Knock joke?

Just think for a minute. The idea of coming up with a humorous statement was certainly in existence long before then. But the Knock-Knock joke seems out of nowhere to anyone who has never heard it before. How did it begin? A possibility:

Ug the Komik: Hey, Ug, I've got a joke!
Ug the Audience: You already told me. "To get to the other side", ha ha ha. Shut up.
Ug the Komik: It's not that chicken one again. It's new!
Ug the Audience: A new joke? Is that possible? It's not the one with the guy that bites the other guy...
Ug the Komik: No, Ug. I made it up myself. OK, here's how it works: Knock Knock
Ug the Audience: ...
Ug the Komik: Now you say "who's there?"
Ug the Audience:I know who's there. It's Ug!
Ug the Komik: No, no... pretend there's a door between us... a piece of wood... A really big rock we can't see around or walk around, but can hear though. Just say who's there
Ug the Audience: But I don't know who's there. It's your joke, and I'm not telling it for you.
Ug the Komik: Yeah, but... Just say "Who's there?"
Ug the Audience: OK. who's there?
Ug the Komik: Uh... Boo!
Ug the Audience:... Yes?
Ug the Komik: Now, you say Boo who... God damn it!!!
Ug the Audience: What? Which god? And why are you crying?
Ug the Komik: Never mind!

As you can see, the first Knock-Knock Joke was unsuccessful.
Which of course, is a proud tradition that has continued through the ages.