Who was he?

Marquis de Sade was a French aristocrat, revolutionary, and writer. He's most famous for bringing explicit material to people in a time when showing off your ankles was scandalous.

Why is he famous?

Marquis de Sade became famous for his libertine sexuality and lifestyle (i.e., a person without moral restraint), but mostly for his suggestive novels. He also left the world with the practice of S&M. That's right, the man invented S&M. How? Well, first of all, it's named after him.

The term "sadism" is based on Marquis de Sade: the idea of developing pleasure as a result of inflicting pain. "Masochism" is first seen in some of Sade's more Gothic-inclined sexual novels, where, for example, the female character is bound and tormented, but also fondled, and develops a kind of attraction to her tormentors.

So, why is he a pervert?

Sade's tales include that time when he and his wife kept five young women and one young man captive in their house. For six weeks, Sade used his victims for sex. He would even lure young women from the surrounding village by drugging them with a "Spanish fly" aphrodisiac.

He spent the last 13 years of his life in an insane asylum, before he perished in 1814.