Before the invention of the printing press, the only way to make a copy of a text was by hand. Whether intentionally or by accident, the copy was not always identical to the original and the differences carried over to all other copies made from the new version. This is also similar to how genetic mutations spread in populations throughout evolutionary history.

Similarities between species genealogy and manuscript genealogy were first noticed in the 19th century, says Julien Randon-Furling, a mathematician at the Borelli Center at the École normale supérieure Paris-Saclay. popular science. Randon-Furling studies the intersection of mathematical sciences and the humanities, among other disciplines.

Following in the footsteps of scholar Michael P. Weitzman, who in the 1970s and 1980s applied mathematics to manuscript genealogy, he and his colleagues used computer models to reconstruct and simulate the spread of chivalric narratives beginning in the year 1100. Chivalric literature is a genre dating back to medieval times that frequently portrays the adventures of knights.

By reconstructing the branches of how various medieval texts were copied and spread over the centuries, the team was able to estimate how much of the entire tree survived. Their results, published in PNAS Nexus study, indicate that up to 60 percent of chivalric texts and more than 95 percent of chivalric manuscripts could have been lost to history. While this may seem extreme, it actually reinforces previous theories.

“Philologists and historians have known for a long time that the amount of losses was impressive,” explains Ulysse Godreau, co-author of the study and postdoctoral researcher at the National School of Letters at the University of Sciences and Letters in Paris. The team wanted to “confirm or confirm these estimates and perhaps enrich them through more dynamic quantitative studies.”

In fact, what makes this study unique is how it understands the genealogy of manuscripts and the resistance of texts as a dynamic process, according to Jean-Baptiste Camps, the study’s principal investigator and a computational philologist at the École nationale des chartes, Paris Sciences & Lettres University. Their approach takes into account time as an influential factor. It also considers the consequences of events such as wars, pandemics, or even the declining popularity of a work on textual genealogy, allowing researchers to align the proposed theory with historical information.

Perhaps not surprisingly, if only a few copies of a text were made in its early years, it is very likely to have been lost, another factor that was included and quantified in their computer models. The team’s study indicates that, due to this and other possible reasons (random accidents, important historical events such as the plague), the original version of most chivalric texts has probably disappeared.

While the study may seem daunting, it provides a tool to better understand not only history, but what we don’t know about that history, Randon-Furling emphasizes.

“One of the questions that drove us was: how much of the past do we have in our hands?” he explains. “Because if you tell me that the manuscripts that we have represent 90 percent or even 50 percent or 25 percent of what existed, or whether they represent less than 5 percent of what existed, it’s a completely different story, a completely different picture of the past.”

Now, the team aims to investigate the genealogy of even older texts, such as ancient Greek plays. The team has already tested the texts of the Church Fathers.

Furthermore, the researchers say they plan to “expand our approach by taking into account cultural transfers between different regions and languages ​​of medieval Europe, from France to Iceland or Spain. Different regions could function as different ‘ecosystems’, with different results in terms of text diversity or their survival,” explains Camps. “Some elements already hint at differences between ‘island’ and continental environments.”

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