The Buried Books of Numa Pompilius

In 181 BCE, on a plot of land belonging to a scribe named Lucius Petilius, on the slope of the Janiculan Hill, farm workers turned up two stone chests. Both were inscribed, in Greek and Latin letters, saying who lay inside.

The first held bones. The inscription named them as Numa Pompilius, second king of Rome, dead for more than five hundred years by the Roman reckoning of the time. The second chest held books.

Rome had just found its founding king's private library. And within days, the Senate had most of it burned.

A king, and his unread writings

Livy tells the story straight: word reached the urban praetor, Quintus Petilius, who opened the second chest and read what was inside. He reported to the Senate that the books were, in his judgement, subversive of the religion Rome currently practised. The Senate agreed with him without much apparent debate. The bones were reburied undisturbed. The books were burned in the Comitium, in public, by attendants under Petilius's direction.

That much is close to consensus among the sources. Almost everything else about the books, what was actually in them, is not.

Four historians, four different books

Pliny the Elder collected the variants a couple of centuries later, and they do not sit well together. Piso, a former censor, said there were seven volumes on pontifical law in Latin and seven more on Pythagorean philosophy in Greek. Tuditanus said twelve volumes of Numa's decrees, full stop. Varro counted seven books he called "Antiquities of Man" and gave no further detail. Valerius Antias went further than any of them: twelve books on pontifical matters in Latin, and twelve more in Greek on "doctrines of philosophy."

Cassius Hemina, writing earlier than any of these, skips the count entirely and simply says the books were philosophy, which is why Petilius burned them.

Four writers, none of them in agreement on the number of books, the language split, or exactly what "philosophy" meant in a text supposedly composed by a king who ruled around 700 BCE. This is not a case of one detail blurring with retelling. It is four separate reconstructions of an object that, by the time any of these men wrote, had been ash for decades.

The claim Livy himself refuses to believe

The most famous version of the story, that Numa's Greek books were Pythagorean, is also the one a Roman historian flatly rejected in his own text.

Livy states the problem plainly: Pythagoras did not arrive in southern Italy and begin teaching until the reign of Servius Tullius, generations after Numa's traditional dates. A king who died before Pythagoras was born could not have been his student, whatever anyone wanted to believe about where Rome's religious wisdom had come from.

Livy attributes the Pythagorean claim to Valerius Antias and moves on, visibly unimpressed. Recent scholarship has complicated even that much. In a 2024 article, the classicist J. H. Richardson argues that Livy's version of what Antias actually wrote may not be a fair summary: the surviving fragments of Antias do not obviously support the specific Pythagorean claim Livy attributes to him, and Livy had a track record of finding fault with the sources he was rewriting. It's possible the whole "Pythagorean forgery" element of the story owes as much to Livy's own scepticism about a rival historian as to anything Antias wrote.

Either way, the detail that made the story famous, a king secretly trained by a Greek sage, may be a modern myth built on an ancient one.

A completely different story, from a different angle

Then there is Augustine, writing in the fifth century CE and drawing on Varro, who gives an account that barely resembles Livy's at all.

In this version, Numa did not lose the books by accident of history. He buried them himself, deliberately, because he judged their contents unfit for anyone to read. A ploughman found them centuries later and handed them to a magistrate. The Senate burned them anyway, and Augustine offers his own theory for why: the books may have revealed unflattering truths about the nature of Rome's gods, that they were petty and demanding, or, worse for the priesthood's purposes, simply dead men elevated to divine status after the fact.

Notice what has changed. In Livy, the books are a hazard because of foreign philosophy contaminating Roman practice. In Augustine's Varro-derived version, the danger is theological: not where the ideas came from, but what they said about the gods Rome actually worshipped. Same chest, same burning, two entirely different reasons a Roman state needed it gone.

A burning with a sequel

Numa's books were not the only prophetic writings Rome destroyed for the safety of its own religion. Some hundred and seventy years after Petilius's bonfire, Augustus organised a much larger burning of his own: more than two thousand unlicensed prophetic books swept up from across the city and destroyed, while the officially sanctioned Sibylline Books were quietly edited and moved next door to his house.

The two episodes make an odd pair. Augustus burned what was unauthorised and kept what carried state approval, then relocated the approved version somewhere he personally controlled. The Senate of 181 BCE had no such convenient category. Numa's books were not some anonymous pamphlet in circulation; they were attributed to Rome's own founding lawgiver, discovered in his own grave, arguably as authoritative a source as Roman religion could produce. And the Senate burned them anyway, without keeping a curated remainder.

What survives is not the books. It's the argument about them, conducted across five centuries by writers who never saw a page, using each other's guesses as evidence. Livy doubted Antias. Augustine used Varro to correct Livy's whole framing. Modern scholars now doubt whether Livy represented Antias fairly in the first place. The books were burned in an afternoon. The disagreement about what was in them is still going.