Artificial Intelligence Can Now Decipher Medieval Graffiti (Cat Sketches and All)

Researchers sought to decipher the 11th-century graffiti adorning the walls of St. Sophia’s Cathedral in Kiev

The graffiti found on St. Sophia's walls includes sketches of cats, business announcements and invocations of medieval curses Wikimedia Commons

The gold-capped spires of St. Sophia’s Cathedral tower over the landscape of Ukraine’s capital as one of the city’s most significant historical sites. The 11th-century house of worship provides a monumental reminder of Kiev’s spot at the crossroads of East and West, as well as surprising insights into the everyday lives of Kiev’s residents: Some 300 pieces of medieval graffiti scrawled on its walls capture a community’s daydreams and worries, from a forlorn young woman’s hopes of attracting a male suitor to condemnations of thieves and sketches of cats.

Now, Venture Beat’s Kyle Wiggers reports that researchers from the National Technical University of Ukraine and Huizhou University’s School of Information Science and Technology have created a machine learning model that “detects, isolates and classifies [the] ancient letters” scattered across St. Sophia’s stone walls.

The team’s findings, newly published in pre-print server Arxiv, drew on a database featuring more than 4,000 images of 34 glyphs, or hieroglyphic symbols, commonly found in the Glagolitic and Cyrillic alphabets. According to the study, the roughly 7,000 individual glyphs adorning St. Sophia represent both Slavic scripts, although specific lettering varies by style, arrangement and layout. The medium chosen by these early graffiti artists posed an obstacle for researchers, as stone carved handwriting is typically of much lower quality than texts written with pen, pencil, stylus or even one’s finger.

To train their convolutional neural network—a machine learning algorithm typically used to analyze visual imagery—the scientists relied on the specially created database of the Glagolitic and Cyrillic glyphs, as well as notMNIST, an image recognition dataset of publicly available fonts including different variations of the letters A through J.

The team’s neural network exhibited 99 percent accuracy when isolating characters from both datasets, Wiggers notes.

Moving forward, the researchers hope to finetune the model’s understanding of aspects such as “date, language, authorship, genuineness, and meaning of graffiti.” They also aspire to build larger databases of early glyphs, which will be shared “around the world in the spirit of open science, volunteer data collection, processing and computing.”

The Daily Beast’s Scott Bay notes St. Sophia can trace its beginnings to the reign of Vladimir the Great, a Grand Prince of Kievan Rus. The cathedral’s foundation was laid in the early 11th century, but the bulk of its construction occurred during the mid-11th century under the watchful eye of Vladimir’s son, Prince Yaroslav the Wise.

According to Ukraine Today, historian Vyacheslav Kornienko has extensively researched the cathedral’s graffiti. His studies suggest that lower-class residents were more literate than previously believed, refuting the idea that only clergy and the elite knew how to write.

One of the most unique markings left on St. Sophia’s walls is an announcement of Yaroslav’s death. Other records focus on less momentous subjects. A woman named Olena carved out a prayer to her namesake saint, requesting aid in winning over a male lover, and multiple individuals left behind sketches of cats. One local left a curse on a fellow Kievan, writing, “Kozma is a thief. Stolen meat. May your legs twist. Amen.”

Members of Kiev’s nobility decided to leave their signatures, too: As travel blogger Mariana Noble reports, Yaroslav and his sons, Sviatoslav and Vsevolod, all scratched out their names on the church’s walls.

It’s quite a stretch to compare these early graffitists to contemporaries like Banksy and Keith Haring, but few admire the scribbles on view at St. Sophia’s solely for their artistic value. Instead, these centuries-old carvings offer a window into a medieval world filled—much like today—with unrequited love, mundane squabbles and cute animals drawings.

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