1. It was written in roughly 120 hours, over 37 consecutive days.
2. It was written on sheets of paper glued together to form a scroll 11cm wide and 12 metres long, which Sade kept in a copper cylinder.
3. Sade failed in his attempt to smuggle an earlier version of the story out of prison.
4. Sade features in one of the passions described on the 23rd Day as ‘the Marquis de …’
5. There are actually over 140 Days of Sodom – as the libertines arrive in Silling Castle on 29th October and don’t leave the castle before 20th March (their departure delayed by bad weather).
6. Silling Castle moves from Switzerland to the Black Forest in Germany in the course of the introduction.
7. Sade was moved from the Bastille prison on 3rd July 1789, just 11 days before it was stormed in the Revolution, and he never saw the scroll again.
8. It was first published in 1904 by Iwan Bloch, a pioneering sexologist.
9. Samuel Beckett almost translated it for the Obelisk Press in Paris in the 1930s.
10. A private foundation, Aristophil, paid €7 million for the scroll in 2014.