Let us start near the very beginning..with Ptolemy. Even though most of his theories have been discredited over the millenia, the man himself is still recognised as one of the early greats. Err..that is, outside the scientific community. Inside the community people began wondering how he managed to carry on so many detailed experiments.
And the answer for posterity is?....he did not. He stole experiments from others and when they were not available he simply made up data that fit his theories. Of course this means that rather than being one of the early great scientists, he gave politicians something to strive for,eh?