> This actually helps explain the rather puzzling behaviour on the part of royal courts: after all, since kings usually controlled the gold and silver mines, what exactly was the point of stamping bits of the stuff with your face on it, dumping it on the civilian population, and then demanding they give it back to you again as taxes? It only makes sense if levying taxes was really a way to force everyone to acquire coins, so as to facilitate the rise of markets, since markets were convenient to have around.

And that's still a very good story for the "backing" of our modern currencies. Apart from the effects of having stable equilibrium, i.e. everyone excepts currency because everyone else does--which is probably the much bigger effect in anything but the very long term.