[winestock]

Orson Wells came up with that line in the motion picture _The Third Man_. The screenwriters didn't come up with it. The author of the original novel didn't come up with it either (though he liked it). There was a space of time in the film that needed to be filled, so Orson Wells filled it.

The full quote is:

Like the fella says, in Italy for 30 years under the Borgias they had warfare, terror, murder, and bloodshed, but they produced Michelangelo, Leonardo da Vinci, and the Renaissance. In Switzerland they had brotherly love — they had 500 years of democracy and peace, and what did that produce? The cuckoo clock.