Why Were the Catacombs Built? Rome and Paris Disagree

In 1774, three hundred metres of a public road on the southern edge of Paris stopped being a road. The street now called Denfert-Rochereau dropped into the ground, into tunnels the city had spent centuries cutting beneath itself to quarry out the stone its own buildings were made of.

Twelve years later those tunnels were blessed and consecrated, and carts began arriving after dark, loaded with the dead.

That is one half of the answer. The other half happened in Rome, sixteen centuries earlier, and has almost nothing in common with it.

Why were the catacombs built?

Two different places, two different reasons. Rome’s catacombs were legal cemeteries, dug downward into soft volcanic rock because Roman law banned burial inside the city and the roadside burial grounds outside were already crowded. Paris’s catacombs were disused limestone quarries, converted into an emergency ossuary in 1786 after the mines began collapsing and the city’s graveyards overflowed.

Rome went down because the law kept the dead outside

The Roman law code known as the Twelve Tables opens its section on sacred law with a flat instruction: “A dead person shall not be buried or burned in the city.” Every cemetery therefore sat outside the walls along the consular roads, and the tombs on a road like the Via Appia formed “an almost uninterrupted street for many miles from the gates of the city”.

Christians and Jews made that squeeze worse by burying their dead instead of burning them. A body needs far more room than an urn. The Catholic Encyclopedia’s article on the catacombs sets the two customs side by side: Romans “cremated their dead and deposited the ashes in a family tomb”, while “the Jews living in Rome retained their native method of burial”.

Rome’s way out was geology. The Pontifical Commission for Sacred Archaeology records that the catacombs were “for the most part, excavated in tuff”, a volcanic ground it calls “easily removable but solid”, and that they cluster “especially where there are tufacious types of soil”. A community running out of surface took the ground underneath instead. The Catacombs of San Callisto run “about 12 miles long, in four levels, more than twenty meters deep”, and their custodians count roughly half a million Christian burials there, including sixteen popes.

The Romans did not call any of this a catacomb. They called it a cemetery, from the Greek koimeterion, “sleeping place, dormitory”, an ordinary word that early Christian writers were the first to use for a burial ground. What a thing ends up being called is rarely what it was called first, which is the same knot behind the argument over flags flown low.

The hiding-place story is Victorian, not Roman

The familiar picture has persecuted Christians tunnelling out a refuge and holding secret Mass underground while soldiers search the streets above. One sentence from a Roman official takes it apart.

In 257, during the persecution under the emperor Valerian, the prefect Aemilianus sentenced the bishop Dionysius of Alexandria to exile and attached a condition, preserved by Eusebius: it “shall by no means be permitted you or any others, either to hold assemblies, or to enter into the so called cemeteries.”

You cannot ban people from a hiding place whose address you do not have. The order Aemilianus read out, “at the command of our sovereigns”, is evidence that the Roman state knew exactly where the Christian cemeteries were.

The prefect is even using the Christians’ own new word for the places. Jerome, studying in Rome as a young man in the fourth century, remembered them as an outing rather than a bolthole: “When I was a youth in Rome, studying liberal arts, it was my custom on Sundays… to visit the sepulchers of the apostles and martyrs.” He lived to see the city taken: when Alaric’s Goths sacked Rome in 410, Jerome wrote that “sobs choke my utterance”.

The underground-congregation image is a staple of nineteenth-century fiction. Nicholas Wiseman gave his 1854 novel the title Fabiola; or, The Church of the Catacombs, which tells you what readers were being sold. Hiding from a persecuting emperor is also the heart of San Marino’s founding legend, in which a Christian stonemason named Marinus fled Diocletian to Mount Titano, the source of the republic’s traditional date of 301. Old spaces collect stories nobody asked for, much like the eye that stares out of the dollar bill.

Paris inherited its catacombs from quarrymen

Everything under Paris was a hole first. The Lutetian limestone that built the Louvre, the churches and the city walls came from directly beneath the streets, cut in open pits in antiquity and then underground from the Middle Ages on. By the 1770s those workings were failing, and the official history of the site records the turning point without decoration: “1774: severe collapse of Rue Denfert-Rochereau; 300 meters were swallowed up.” On 15 September 1776 Louis XVI signed a decree that “definitively prohibits extracting material from under public roads”, and on 4 April 1777 he created the Department of General Quarry Inspection, charged with “protecting Parisian quarries”.

The second problem was on the surface. The Saints-Innocents cemetery closed in 1780 after what the city records as “consecutive use for nearly ten centuries”, and “major public health problems tied to the city’s cemeteries” settled where its contents would go. Paris now had too many dead and, directly beneath them, a great deal of surveyed empty space.

On 7 April 1786 the Tombe-Issoire quarries were blessed and consecrated as the municipal ossuary. Bones came out of Saints-Innocents between 1785 and 1787, and out of other parish grounds until 1814, and they travelled at night, “to avoid hostile reactions from the Parisian population and the Church”.

From 1809 the ossuary took visitors by appointment. It now moves about 550,000 people a year along a 1,500-metre circuit, 20 metres underground, past the remains of several million Parisians.

	Rome	Paris
Dug as	A cemetery	A stone quarry
Rock	Volcanic tufa	Limestone
Cut by	Burial communities, 2nd to 5th century	Quarrymen, over centuries of building the city
How the dead arrived	Buried there as people died	Carted in from closed graveyards
Got the name	Inherited from one Roman site	Applied in 1786

The word came from one dip in the ground

“Catacomb” started as an address. The International Catacomb Society traces it to Greek kata kumbas, Latin ad catacumbas, roughly “near the hollows”, and reads it as “a topographical reference to the site of a first-century pagan cemetery between the second and third milestones of the Appian Way”, a cemetery lying “in a deep hollow, a former quarry”. That one site, the complex of St Sebastian on the Appian Way, was the catacomb. Everywhere else was a cemetery.

The origin is disputed. The Online Etymology Dictionary calls it obscure and offers Latin cata tumbas, “at the graves”, as one candidate, while allowing that the word may have been a proper name to begin with. Either way it generalised late: Paris claimed it for the Tombe-Issoire quarries in 1786, and English stretched it to “any subterranean receptacle of the dead” only by 1836. A French limestone mine therefore ended up wearing a name coined for a hollow in Italian volcanic rock, roughly the sort of accident that left a ship’s rearmost deck with a name that makes visitors snigger.

Rome’s dead went underground because the law and an already crowded strip of roadside left nowhere else to put them. Paris’s dead went underground because the holes were already there and the graveyards had shut. Both cities were solving a shortage of space, sixteen centuries apart, and only one of them ever set out to dig a cemetery. Strictly FYI.