The most famous quote attributed to Voltaire is “I disapprove of what you say, but I will defend to the death your right to say it”. The problem is that he never said or wrote it. It was written in an early 20th century biography about him. However he did spend 11 months in the Bastille after an affair with a French Protestant caused a scandal. The Bastille was not the horrible dungeon depicted in movies and Voltaire started many of his most famous writings while he was there.

(The Great Courses – Voltaire and the Triumph of Enlightenment)