You question lacks specificity. Are you asking if there has ever been an example of a peaceful protest movement that has toppled a regime/government? Moreover, how are we defining "violent protest?" Is it merely bloodshed? Or would the destruction of symbols (e.g., statues, religious icons, monuments) also be considered violence? In any case, I'm pretty sure your hypothesis can be quite easily refuted. There are countless examples of entirely peaceful protest movements overturning governments. The 1989 revolutions in Czechoslovakia and East Germany are but two examples of a peaceful revolution.

Sorry, we don't allow throughout history questions. These tend to produce threads which are collections of trivia, not the in-depth discussions about a particular topic we're looking for. If you're interested in a specific region/culture(s) and preferably time-period, please feel free to re-compose your question and submit it again.

BTW, this question may also be appropriate for /r/AskSocialScience, although note they they also have a rule requiring questions to be focused.