the only pre-keynes material I have been able to find is keynes' ideological predecessor Jeremy Bentham. Keynes is the one who popularized the approach and introduced policies that were actually adopted by government. control over monetary expansion to the degree that is required wasn't possible until the Federal Reserve was established.

When I say that keynes created the fetish of full employment, I mean that post-keynes it was a continuing concern of government, whereas pre-keynes it had not been.