No such luck. For almost two centuries, scholars, critics and fellow artists have been rooting about in Sade’s grave in an effort to form a conclusive portrait of the man. Opinions are wildly divergent. Some heavy-duty thinkers - Artaud, Nietzsche, Kraft-Ebbing, Angela Carter and Camille Paglia among them - rank Sade as an overlooked genius, a ‘Professor Emeritus of Evil’. A few even praise Justine as a work to rival the satire of Jonathan Swift. The Surrealists adopted Sade as their patron Saint, citing him as “the freest spirit who ever lived”. Others - like Louis Bongie and Roger Shattuck - are far less generous.

They’re loath to see Sade resurrected at all. His writing is attacked as monotonous, his philosophy sophomoric and his impact on the world of letters merely toxic. They claim that his sole contribution to world culture is entomological at best: the term ‘sadism’ is derived from his name. Shattuck even calls Sade a “vicious evangelist”, and suggests that he is culpable for inciting the Moors murders of 1965 and the serial killings of Ted Bundy.

Whose assessment is correct? Was Sade a vile pornographer or an oft-maligned genius? Or (more troubling still) was he both at once? Sade’s fiction is more extreme than anything we might find in contemporary culture. His prose is scathingly funny one minute, repugnant the next; it careens from acute social satire to masturbatory fantasies to scenes so depraved - so preposterous - they set a new benchmark for perversity in literature. In Sade’s 1795 novel Philosophy of the Boudoir, an elderly dowager is forcibly infected with syphilis. In Justine (1791), a vampiric husband ritually bleeds his wife to death. And in Juliette (1797), Sade’s most monstrous heroine performs a black mass with the Pope, disembowelling a pregnant waif on the Vatican’s altar.

Coprophilia, mutilation, necrophilia and pederasty are staples of Sade’s oeuvre. Intercut with these prolonged sexual escapades are philosophical diatribes more nihilistic than Nieztsche. Chaos reigns supreme in a Godless universe, brute strength trumps morality at every turn and violence is the only sure route to pleasure.

Read in sequence, Sade’s novels do, in fact, offer a compelling (and unintended) profile of their author. It is impossible to separate the writing itself from the circumstances in which Sade wrote: a fallen aristocrat who weathered the French Revolution, he spent over 30 years of his adult life in prison, for crimes ranging from rape to pornography. His tales were hatched in dungeons, prison apartments and mental asylums throughout late 18th-century France. The stories seem to spring like gorgons from a vast, ever-replenished well of rage. Sade writes to vent his fury at the hypocritical forces which oppress him; to stave off his own madness; and to gratify himself carnally in the confines of prison, in fantasies which escalate with the correlative length of his interment. All his volcanic emotions, entombed within four walls for almost half his adult-life, erupt onto parchment with the force of a natural disaster. One moment, he is grandiose; the next, infantile. Like many of his characters, Sade registers as an amalgam of our basest appetites, stripped bare. He is grotesque and seductive at the same time.

Because Sade so completely synthesises the romantic notion of the ‘writer as madman’, he’s been a potent Rorschach for many other artists: Peter Weiss, Yukio Mishima, Nobel prize-winner Octavio Paz and the film-maker Pier Paolo Pasolini have all forged work based on Sade’s canon. (Unsurprisingly, most of Sade’s fellow artists tend to adopt a comparatively sympathetic view.) And, given the extremity of his prose, Sade raises inevitable and necessary questions about the very nature of art. What is its true function in a culture? To uphold society’s tenets, or to challenge them? To reassure, or to agitate? To buttress those institutions which shape civilizations - the government, the church - or to expose them? Does political oppression actually breed (rather than stifle) provocative art? What happens when we silence our extremists? What happens when we give them voice?

As I began to write Quills, these questions were more important to me than a literal, biographical account of Sade’s life. Real lives rarely have narrative and thematic continuity, and they can seldom be compressed into two hours. Furthermore, I could never claim the Sade I conjured would be ‘accurate’. Inevitably, he would be a jumble of assorted facts and my own suppositions. So I gave myself a gift - that liberating concept known as ‘poetic license’. I knew that if I truly wanted to convey Sade’s spirit - not the raw data of his life, but his own dark, venomous aesthetic - I would need to draw as much upon his fiction as I would upon the ever-growing pile of biographies upon my desk; to write with the same malicious glee Sade himself must have felt as he catapulted his way through 120 Days of Sodom or Justine. I’ve re-ordered facts, forged composite characters and created new ones. Many of the film’s climactic moments are purely fictitious. I’ve even put words in the late Marquis’ mouth, composing stories in his style rather than plagiarise his novels.

I hope the film reaches beyond the notorious man at its centre to speak to a 21st-century audience. I’ve endeavored to follow the example of my betters, plucking Sade from the musty pages of history in an attempt to address critical issues in our time. I pray that he doesn’t mind the intrusion, especially in light of his last request. I’d hate to be on his bad side.