We’ve all taken a piece of paper out of the recycling to jot down a shopping list or a phone message. Now imagine trying to piece together a history based, not on the notes, but what was on the other side of the paper.

That’s the work of Marina Rustow, who was named a Macarthur Fellow (sometimes known as the Macarthur “genius grants”) last fall to study documents in the Cairo Geniza.

First of all, what is a geniza (sometimes spelled genizah)? An ancient Jewish custom prohibits the destruction of pieces of sacred writing—in theory, fragments of the Bible containing God’s name, but in practice anything copied or printed in the Hebrew script, writes Mark Cohen, Khedouri A. Zilkha Professor of Jewish Civilization in the Near East, Emeritus, of Princeton University, in History as Prelude: Muslims and Jews in the Medieval Mediterranean. These papers must be hidden or buried in a geniza, typically located in a cemetery. “Every Jewish community in the Middle Ages had a geniza, and burial of worn pages from Hebrew books is still practiced by traditional Jews around the world today,” he writes.

The Cairo Geniza is not the only such repository, but it is one of the most well-known. Discovered in the late 19th century, it was special because it was inside a synagogue that dates back at least to the Middle Ages, Cohen writes. This meant the contents were concentrated in one place and easily accessible, once discovered. In addition, because Egypt has an arid climate, the pages survived in good condition. “Even when a page is torn or riddled with holes, the ink can be read today almost as clearly as when it was copied, in some cases as long ago as a thousand years,” he writes. Some of the documents were a thousand years old.

More than 400,000 fragments in the Cairo Geniza have also been photographed and entered into a database, in a project that took more than five years, writes Yaacov Choueka, Chief Computer Scientist for the Friedberg Genizah Project.

This database was important because components of the Cairo Geniza were located in libraries all over the world. Even two fragments from the same page might be separated by thousands of miles, Choueka writes. Digitizing the documents meant that scholars could look at them without having to travel to multiple locations.

“You used to have to travel or look at microfilm, and you could have the top half of a letter in Cambridge and the bottom in New York, and unless you had a photographic memory, or took detailed notes, it was difficult to piece things together,” Rustow tells The Jewish Week. “Now, I can sit in the comfort of my own living room in pajamas and look at a torn folio the way its scribe would have seen it.”

The database also lets researchers try putting together document fragments like a jigsaw puzzle. In addition, in 2013, the project used a supercomputer system for five weeks to run an algorithm to systematically look for such connections.

That means the Cairo Geniza has become a rich source of information about the day-to-day life of Jews in that time period and location.

Rustow, however, took this research a step further than just studying the Hebrew writings. As we know, when writing material was scarce, people would take discarded parchment and other materials and use it. Think of it as ancient recycling. This was also true of Cairo Jews. But the material they often wrote on was discarded Egyptian government documents, because that’s what they had handy.

In addition, Egyptian government documents also ended up getting placed in the geniza along with the more sacred works. “Periodically, when cleaning house, these piles containing fragments of books (Islamic as well as Jewish), as well as letters and other non-religious documents, would be carried to the synagogue to be buried in the Geniza,” Cohen explains. “Rather than sorting through to find pages that contained something ‘religious,’ everything was removed to the Geniza.”

Consequently, researchers have found all sorts of documents in the Cairo Geniza: “Shopping lists, marriage contracts, divorce deeds, pages from Arabic fables, works of Sufi and Shi’ite philosophy, medical books, magical amulets, business letters and accounts, and hundreds of letters,” writes the Cambridge Digital Library, which owns a collection of documents from the Cairo Geniza. “Examples of practically every kind of written text produced by the Jewish communities of the Near East can now be found in the Genizah Collection, and it presents an unparalleled insight into the medieval Jewish world.”

So Rustow, knowing Hebrew as well as Arabic and other languages used in Egypt, began studying the information that she could glean from these approximately 10,000 to 15,000 administrative documents.

“It’s as if we’ve found a diary that was written on supermarket receipts, and instead of being concerned with the diary, you’re looking at what people actually bought at the supermarket,” explains Robert Siegel of NPR.

So far, about 4,300 of the administrative documents have been transcribed into a computer database, according to Cohen. He has now retired from the project and Rustow has succeeded him in that position, including directing the Princeton Geniza Lab.

Digitizing the documents also makes them more useful for scholars in the years to come, Choueka writes, making a good argument for electronic documents in general. “A digital image is necessary also because it is the only format a computer can ‘understand’ and analyze,” he writes. “If we make the effort of digitizing the manuscript with the parameters best suited to computer use, it will reward us a hundred times over by supplying us with data, information and suggestions that may save us a lot of tedious labor, and maybe also point us in interesting new directions in our research tasks.”

Photograph by Younes and Soraya Nazarian Library, University of Haifa & The Friedberg Genizah Project [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons