When you think of the priceless treasures at the Vatican Museum you probably think of the artwork: Michelangelo’s Last Judgment and the ceiling of the Sistine Chapel; the Pieta in Saint Peter’s; the ancient and renaissance artwork in the Museums; or even the priceless manuscripts and precious coins hidden away in the libraries. If you’re like me, you probably don’t jump to toilette furniture. All the same, one of the most valuable items in Rome is a bathtub that has been estimated to be worth $2 billion. And you thought your bathroom renovation was expensive.
The bathtub—more technically known as a “porphyry basin”—is today housed in the round hall in the Pio Clementino Museum. It was commissioned by the first-century Roman emperor Nero for his famously decadent architectural vanity project the Domus Aurea (Golden House). Built entirely of purple stone, the basin weighs more than 1,000 pounds. Over drinks at a recent Bible conference (I know, fun!) Eric Vanden Eykel, an associate professor of religion at Ferrum College, and I discussed the bathtub and its hefty price tag.
The reason it is so expensive, Vanden Eykel told me, is that it “was made from an extremely rare and therefore expensive marble called ‘imperial porphyry.’ Nero and other emperors liked this stone because of its deep and distinctive purple shade, but it also didn’t hurt that it was exclusive and extremely hard to come by.”
All imperial porphyry mined in the ancient world came from a single, remote quarry in the eastern part of Roman Egypt called the Mons Porphyrites. It was discovered in 18 B.C. when a Roman soldier named Caius Cominius Leugas noticed a hard purple-red rock in the desert. Technically porphyry (which just means “purple” in Greek) is an igneous rock containing coarse grained crystals. Most imperial purple marble was used as an accent stone in tiled floors or on columns. You can find it fashioned into vases or busts, but the basin from Nero’s Golden House is exceptionally large and heavy. It’s almost certainly the largest single intact piece of porphyry marble that exists today. The mine established at Mons Pophryites was used continuously until A.D. 600, when the Romans lost control of Egypt.
After it was extracted from the mines—which was no mean feat!—the material had to be transported. The journey began with a lengthy overland journey from the mine to the Nile. At Coptos, the marble boarded a ship up the river and carried on across the Mediterranean making stops along the way. The final leg of the journey, from the port of Ostia to the City of Rome also took place over land. Even for those not transporting heavy marble this was a lengthy journey that could take as long as 10 weeks. As Incunabula has put it on Twitter: “Imperial porphyry signaled not just power and prestige, but also that the Roman Empire could accomplish the near impossible: Cutting and quarrying the immensely hard rock, and transporting it 1000s of kms from the Egyptian desert to Rome was an awe-inspiring feat of engineering.”
It was the expense of moving the stuff that made imperial porphyry so expensive and exclusive. Vanden Eykel told me that imperial marble is immediately recognizable because of its distinctive marble hue. It signifies wealth and status. Just as having a white alligator Hermes Birkin says that you have connections and $150,000 to burn on a handbag, porphyry marble signaled to your guests that you were someone of import. What says that more, said Vanden Eykel, than “a gargantuan porphyry bathtub?” The only other porphyry objects of similar scale were tombs and coffins: Nero, the Holy Roman Emperors, and even Napoleon all chose it for their final resting places. Napoleon had to make do with a common red marble.
The Roman obsession with imperial purple went beyond marbles. They were equally obsessed with purple textiles and, just like marble, these were expensive. Tyrian or imperial purple dye was made from the desiccated glands of the predatory sea snails found in the Eastern Mediterranean and off the coast of Morocco. The dark purple-red dye was used on ceremonial clothing for high-status individuals; it was particularly valued because it didn’t fade but it was expensive (not to mention smelly) to manufacture. Like an Hermes Birkin and other luxury products, both Tyrian purple and imperial porphyry were regularly imitated. Rosso antico marble (also known as Marmor Taenarium), a beautiful red marble mined in the southern Peloponnese, was one such imitator. It was used, as Lorenzo Lazzarini notes, “as a substitute of the red Egyptian porphyry.” Though it is beautiful, rosso antico lacks the speckles and deep purple of the Egyptian marble. If you wanted to get the imperial porphyry look today, you might try a rosso impero instead.
Though it’s unclear exactly how or by how many people Nero’s bathtub was used, bathtubs have a kind of transhistorical appeal as a symbol of wealth and status. This is despite the fact that at many junctures in history bathing has been associated with debauchery, sexual licentiousness, and disease. The Sun King Louis XIV’s work around was to fill his red bath with odeur de Nerolie, a fashionable 17th-century fragrance made from orange blossom.
The mythology of bathing aside, many of the problems associated with ancient marble continue to plague modern would-be-Neros. Lee Stahl, president of TRH, a design-build company based in New York City, told The Daily Beast that transportation continues to be a problem. Even with modern technology, it’s difficult to move large slabs of marble. Stahl said, “the cost of transporting, insuring, and hoisting marble 14 stories in the air to get it into a building has skyrocketed.” The more things change, it seems, the more they stay the same.
Though Nero’s is the world’s most valuable bathtub, its market value has yet to be proven. Until then the title of most expensive belongs to the Le Grand Queen bathtub, a bathtub designed by Simon Krapf and carved out of Caijou gemstone was sold at auction in 2016 for $1.74 million. It took four years and 120,000 work hours to locate, excavate, and polish the materials into a unique two-person bathtub. Caijou is, technically speaking, 180-million-year-old petrified wood. It is prized by some for its alleged healing and life-extension properties. Perhaps the anonymous buyer wrote it off as a medical expense.