Edward Bernays took the expertise that he had developed when he worked for the US gov't to promote WW1, and applied it in the private sector--that's why they call him "The Father of Public Relations"--but he wasn't really the first--what he did was to write a book that explained the process in psychological terms, aptly titled "Propaganda"--Freud was his uncle-in-law, so he knew the lingo--this, plus a penchant for wholesale self-promotion, made people think that he started the business--not so--

Governments have been using the same PR techniques to gain support for wars since there have been governments--the thing is, though we know all the tricks, and can spot them a mile away, no one has been able to figure out a way to counteract them--