Sade \sȧd\ , Marquis de (Comte Donatien–Alphonse–François) (1740–1814), French soldier and writer. From the time that he was a young nobleman Sade consorted with prostitutes and developed a taste for sexual perversions. He was imprisoned on several occasions for his harsh abuse of prostitutes and gross licentiousness. After arriving at the Bastille in 1784 he began writing erotic novels in which he gave full expression to his sexual fantasies. His most famous novel was The Adversities of Virtue (1787). His works are known for their graphic descriptions of sexual perversions. His last years were spent in an insane asylum at Charenton, where he wrote plays for his fellow inmates to perform. His compulsion for physically and sexually abusing others gave rise to the concept of sadism.