The term "brainwashing" was born in 1950. It is a Chinese word ("xinao", literally wash brain). Originally it served to describe a technique used – so it was claimed – by Chinese masterminds to manipulate the minds of American prisoners in the Korean War. They changed their unconscious mental processes and turned them into agents of sinister forces.
Many books and movies purported to show how this works. For example, the classic film "The Manchurian Candidate" shows how the communists take an American prisoner-of-war in the Korean war, an officer, manipulate his mind and give him an order to kill the US presidential candidate. The American officer does not know that he has been turned unconsciously into a communist agent. He does not remember the order given him under hypnosis and does not know that he acts accordingly.