The oldest known version of a popular 13th-century “romance novel” – featuring a famously risqué sex scene – has been discovered masquerading as the binding of another document.

The fragments of parchment were found by accident in the vaults of the archives of the Diocese of Worcester in the UK, being used as a folder or binding for another manuscript.

Le Roman de la Rose – The Romance of the Rose – tells the story of a courtier wooing his lady love. It was wildly popular in the 14th and 15th centuries, possibly even the most read book in medieval Europe. But the climactic sex scene at the end of the story has often been removed in the retellings for its explicitness.

(We’re going to tell you now, if you are hoping to skip to the good stuff expecting Fifty Shades of Grey, don’t be disappointed when you get Twilight.)

The epic poem is written in two parts. In the first, by Guillaume de Loris in around 1230, the courtier, also known as the Lover or Dreamer, recounts his dream of visiting a walled garden, meeting and falling in love with the Rose – representing both the female lead’s name and all female sexuality – in thrillingly sensual language and imagery (for the time).

In the second part, added by Jean de Meun in 1275, their happiness is short-lived. The Lover must then overcome the forces of resistance and rescue his Rose, ultimately proving successful in “plucking the rosebud”.

“Le Roman de la Rose really was the blockbuster of its day,” said Professor Mariane Ailes from the University of Bristol, who helped identify the new-found texts. “We know how popular it was from the number of surviving manuscripts and fragments, a picture our fragment adds to, and from the number of allusions to the text in other medieval writings.”

“As soon as I saw the pages, I instantly recognised the allegorical name of ‘bel accueil’ – fair welcome – from Le Roman de la Rose and realised that we had something very special and unique on our hands. I also could hardly believe how early the handwriting looked."

The story was so popular it was translated and retold multiple times in multiple languages (famously, even by Chaucer), and many different versions exist – Johns Hopkins has a digital library that currently holds at least 130 versions. The more controversial or raunchy aspects of the tale, which moralists and puritanicals have been getting hot and bothered about over the centuries, have been left out of some versions. In fact, the standard modern French Edition doesn’t include the famous sex scene found in this early version.

So what is all the fuss about? The new pages found by the scholars are a very old version containing the conclusion of the story describing the sexual encounter between the two lovers. The Lover presents himself in front of a shrine equipped with his “staff and “scrip” (a pilgrim’s pouch), the staff described as “stiff and strong”. The Lover recounts past use of his equipment “sticking it into those ditches”, and kneels in front of the shrine full of “agility and vigor, between the two fair pillars... consumed with desire to worship".

The controversy surrounding these passages ranged from outrage at the depiction of the aristocracy acting saucily to the depiction of female sexuality, and surviving original versions that contain this ending are rare.

“The Roman de la Rose was at the centre of a late medieval row between intellectuals about the status of women, so we have the possibility that these specific pages were taken out of their original bindings and recycled by someone who was offended by these scenes,” said Professor Ailes. Now, they will be added to the library of existing fragments of this Medieval bestseller.