Origin of the Riddle of the Sphinx?

Who wrote the riddle of the sphinx? I think there are three, really, correct? The only one I recall is “what first walks on four legs, then two, then three?”, as I recall. Is it from Homer’s Odyssey, perhaps? Dang, it’s gonna bug me!

And, what are the other riddles, if there were three…?

  • Jinx

It’s related in Oedipus Rex by Sophocles, but I don’t know if this is the first record of it. I’m sure it goes back before Sophocles, the Greek tragedians always used familiar legends as the basis for their plays.

Here’s a great link which tells you everything about the Sphinx and the riddle.