When we think of the evilest rulers in history, names like Joseph Stalin, and Mao Zedong rush to mind. But it's important to remember that brutality existed in rulers well before the 1930s.

Others, like Attila the Hun or Chinese Empress Wu, may seem like obvious choices. But after looking deeper at the effects of their rule and how they were perceived by those they reigned over, it becomes clear that they're not the worst rulers in history. Instead, they suffered from then-contemporary historians' ire (Attila because he wasn't Roman, and Wu because she was a woman).