Quick and Hard: Whence the V-4?

If I think of V-4s at all, it’s in connection with Saab. But they didn’t originate it, not by a long shot. I’ve managed to trace it back a ways, but kind of run out of leads after a certain point. So this little puzzler is in two parts: First, what did I find, and second, was it really the first? Here’s your clue–whatcha got?