Congratulations on making it through! 120 Days of Sodom is one of the most god-damned encyclopedic texts I can think of. Tough read.

The Marquis de Sade was willing to conform to a semblance of public life (he had a wife and a child). But was also somewhat notorious for his ill treatment of prostitutes early on. His ruthless behavior in the bedroom (although not rigorously documented) was the subject of rumors in brothels, and he was once even investigated for it. This would not have been completely out of the norm at that time, but for some reason or another (maybe a failure in subtlety) the Marquis was targeted. As Simone De Beauvoir puts it in her essay ["Must We Burn Sade?":] (http://books.google.com/books?id=cYiouOihTnAC&pg=PT17&lpg=PT17&dq=testimony+at+the+Marseille+trial+Sade&source=bl&ots=gXzwtS0Ee7&sig=-a-2JAoXoAg9emAtrPVl_9u7qRE&hl=en&sa=X&ei=VTPYUqzrFs7JsQSIuYLABw&ved=0CDMQ6AEwAQ#v=onepage&q=testimony%20at%20the%20Marseille%20trial%20Sade&f=false)

"Scions of a declining class which had once possessed concrete power, but which no longer retained any real hold on the world, they tried to revive symbolically, in the privacy of the bedchamber, the status for which they were nostalgic: that of the lone and sovereign feudal despot. The orgies of the Duke of Charolais, among others, were bloody and famous."

Sade was imprisoned on multiple occasions for his "excesses," notably in 1763 for the indignities he inflicted upon a beggar named Rose Keller. In this case, Sade was charged with beating Keller, cutting her with a knife, and pouring wax into the wounds. He was imprisoned again in 1771 for debt. And then again, shortly after, in 1772 for sodomizing his manservant and 'poisoning' a prostitute with spanish fly in Marseille. For this last he spent over a decade jailed in Vincennes and then in the Bastille. This is around the time he wrote 120 Days of Sodom, one of "16 historical novellas, 2 volumes of essays, a diary and some 20 plays" that Sade wrote during his long incarceration.

For what it's worth, (in terms of authorial intent) I've always read this text in two lights: as a small (somewhat politicized) rebellion on the part of Sade and as an outlet for his immense boredom. His systematic recounting of acts and repetitive mode of writing reads...almost like a manifesto, as though his private pleasures somehow, at one point or another, transmuted into principles–into an ethics of being.

So it's possible (probable) that Sade acted out many of the debaucheries outlined in 120 Days of Sodom. But I also think his sadism is more projective than impulsive. I think he mainly derived sexual pleasure from the writing in itself.

This is not really an answer to your question, but something for you to consider in your reading of Sade.

The 18th century say a great deal of debate over the novel, what form it should take, and who should write them. In many ways too, it was seen as a debate over public morality, as many writers, the most important of who was Samuel Richardson, thought the novel as written by "those women" (Aphra Behn, Delriver Manley, etc) was immoral, and sensational. So Richardson set out to reform the novel.

Pamela or, Virtue Rewarded, was the sort of novel that set a typology for everything following it—there was a distinct before and after. Pamela was, in some very real ways, Richardson’s “vigorous attempt to reform the romance novel that had been popularized [by women… The work] attempted to redefine the romance novel to make it at once more realistic and more moral.” (Mudge, The Whore's Story, p. 70) And indeed, Pamela is intensely moralistic, its original title page after all, read that it was “designed to inculcate the principles of virtue and religion in the YOUTH of BOTH SEXES… entirely divested of all those images which… tend to inflame the minds they should instruct.”

Despite, or perhaps because of, the fact that Pamela’s plot is more than a little licentious, with its kidnapping and attempted rape of a 15-year-old, Pamela became immensely popular. Not only was it the first major cultural phenomenon—there were Pamela prints and paintings, Pamela playing cards and fans—there were both encouraging and angry reactions. Within a year of its publication, there appeared reactions positive (Pamela Commedia, Pamela’s Conduct in High Life) and negative (Shamela, Pamela Censured, The True Anti-Pamela).

Two other works can also be characterized as reactions to Pamela, and, as it happens, they are the two most notorious works of pornography to originate out of the eighteenth century: Justine, also known as The Misfortunes of Virtue (1742), and Fanny Hill, or Memoirs of a Woman of Pleasure (1748). It would seem to me that 120 Days Of Sodom would also be an example of a anti-moralistic work, where Sade, a libertinist, was taking things to the extreme. You might be interested in my further discussion of Sade here, on /r/literature.

As far as how much Sade drew on actual experiences of libertinism, I am not a sade or a French Scholar, but I can say that the members of the British Hellfire Club may have had some experiences along the lines. It is my opinion (speculation) that Sade was realy just trying to be as offensive and shocking as possible.

p.s. note that both in this comment and in /r/literature I am drawing from my own papers :)

In most French literary circles, Sade is considered canonical and is spoken of in the same breath as Balzac or Flaubert. In spite or because of his work's morally outrageous, pornographic depictions, it is also held up as a prime example of the novelistic form's purportedly inherent push towards absolute freedom. This makes even more sense when you read the Marquis's political and philosophical writings, such as the famous Français, encore un petit effort si vous voulez être républicains (French citizens, try a little harder if you wish to become republican), which can be seen as a rhetorical attempt at spurring a permanent revolution, several decades before Marx was even born.

As another redditor noted, Georges Bataille is one of Sade's greatest exegetes, but I would like to add that his close friend Maurice Blanchot provided an even more fascinating interpretation of Justine and The 120 Days of Sodom's textual labyrinths by emphasizing their polemical streak. Sade's novels are quite similar to his pamphlets in that they are notable for their relentless rhetoric. He tries to persuade the reader of "cruel" nature's superiority over Christian values, constantly punishing those of his characters that have yet to figure out just how vile human beings truly are to each other. In other words, Sade seeks emancipation from social mores and norms, which to him are collective straitjackets, and his means of achieving that goal are primarily verbal and logical, i.e. systematic: he wants to change the reader's mind about human nature, and he will do anything to get his way. Thus, even though he was jailed towards the end of his life, he still tried to write his way out… and into a potential reader's brain.

This is why his grisly eroticism became eponymous and why his name won't be forgotten. By descending further and further, via language, into the least avowable recesses of the human mind, he wished to demonstrate just how appalling we truly are as a race. The only reasonable stance, in such a savage universe, is to become a penetrator rather than a penetratee. It's a form of hardcore libertarianism, albeit in a highly distorted sense. Now, to what extent does this translate into historical reality? We know that Sade himself practiced part of what he preached, so to speak, and abused several of his servants, going as far as cutting and slicing a beggar without her consent. He was undoubtedly quite the psychopath, but though we may never know for sure, it can safely be said that none of his deeds ever went as far as his writings, which remain unrivalled in terms of methodical madness.

So his pornography has a point, which he hammers over and over again, rendering it almost meaningless through endless repetition. To go back to your question, that aspect of his writing is very much of the imagination, a pure figment or fantasy meant to poison his fictional audience's mind and pit it against its own sense of moral self-worth. Following Blanchot, who ascribes Sade's importance to the primarily rhetorical aspect of his writing, I would argue that his work acts like a virus, far from the strictures of realism.

This is anything but a historiographical answer, but there you have it.

From biographies about D A F de Sade; their is documentation of certain hedonistic actions of impulses, such as visiting sex workers at brothels that overlook public hangings et al.. But not to the extremity of eating the excrete of those who are about to be executed for the aroma is simply just tantalising..

120 days written in prison confinement with bitter loathing of privileged social class of which he came from ; Bataille sums up the debauchery quite well as '[a] domain [de Sade] described outside of and above all reality"

Be it his writing as the pinnacle of perversion of morality and is easy to romanticise de Sade in a hagiographic light via his extremity of human fantasy in relation to kink/hedonism. The writing was that, fantasy. It was his pleasure when being confined in a cell, for if fantasy comes a reality all you get is unfulfillment.. the birth of melancholy. de Sade I'm sure realised this.

Sorry if crit theory rhetoric is not agreeable for this sub reddit, but you may like to read Bataille on D A F de Sade for more hagiography.