You might not think of mentioning the Vatican in the same breath as big tech companies like eBay, T-Mobile, and Samsung, but the Vatican Library, which dates back more than half a millennium, is now using the same artificial-intelligence technology as those companies to protect its digitized library.

Over the past decade, the library has been digitizing its entire collection, consisting of more than 80,000 manuscripts, mostly from the Middle Ages but stretching back to the first century (accounting for all the pages of these books, that’s about 40 million images). Envisioned by Pope Nicholas V, the library holds the oldest known copy of the Bible, Virgil’s Aeneid, and writings and drawings by Michelangelo and Galileo. Growing at a rate of about 6,000 volumes a year, the collection also holds major gifts from historical royals like Maximilian I, Duke of Bavaria; the dukes of Urbino; and Queen Christina of Sweden.

“In the era of fake news, these collections play an important role in the fight against misinformation and so defending them against ‘trust attacks’ is critical,” Manlio Miceli, the library’s chief information officer, told the Guardian. He also notes that the library has to protect itself from ransomware.

The library has enlisted Darktrace, a firm founded by mathematicians from the University of Cambridge, to use an artificial intelligence system modeled on the human immune system to repel the threats, which come in at a rate of about 100 per month and are increasing in frequency, Micheli told the Guardian.

The company employs former government intelligence experts across dozens of offices worldwide, and touts its response to the WannaCry ransomware attacks of 2017 as one of its major triumphs.