This video sets out to answer two questions. First, how much – in modern dollars – did
St. Peter’s Basilica cost to build? And second, how much would it cost to build an
exact replica today?
By almost every measure, St. Peter’s Basilica is the biggest church ever built. It’s also
one of the most awe-inspiring buildings on the planet, and among the supreme creations
of the Italian Renaissance.
The scale of the building is staggering. It contains 778 columns, 395 statues, and 44
altars. Before electric lighting, 4,400 lanterns were needed to illuminate the exterior. It
covers 227,000 square feet, and has standing room for 60,000 worshippers.
The construction of St. Peter’s lasted 120 years, and decoration of the interior continued
for another half-century. Although the pace of building varied, as many as 2,500 laborers
were involved in some periods; Pope Sixtus V kept relays of 800 men working 24 hours
a day to finish the great dome.
From the start, and despite such cost-cutting measures as limiting the use of travertine
and scavenging marble columns from ancient ruins, the project was extremely expensive.
Famously, the Protestant Reformation was sparked by a papal scheme to finance construction
by selling indulgences.
The costs of building were counted in the gold coins known as ducats and scudi. Ducats,
modelled on the Florentine florin, contained 3.5 grams of gold. Scudi, which replaced ducats
in the Papal States in 1531, were slightly smaller and contained less pure gold. For
the sake of consistency, I’ve given all amounts in scudi.
Although the records are incomplete, some of the costs associated with the building
of St. Peter’s are known. We know, for example, that in the first year of construction – 1506
– the project cost 13,500 scudi. The bill was 30,000 scudi in 1507, and around 15,000
each year from 1508 to 1510.
For moving the 330-ton Vatican obelisk to its current position in St. Peter’s Square
– a delicate operation that involved 900 men, 75 horses, and 44 colossal winches – Domenico
Fontana was awarded 70,000 scudi.
The dome of St. Peter’s – whose scaffolding used 500,000 pounds of rope – cost 200,000
scudi from base to crown.
The Baldacchino over the high altar also cost about 200,000 scudi.
The cost of building the colonnade around St. Peter’s square was 850,000 scudi. Paving
the piazza took an additional 88,000.
In 1694, at the pope’s request, architect Carlo Fontana estimated the total costs of
building St. Peter’s Basilica. Since there were many gaps in the records, he based his
estimate on the quantity of materials employed in the building. St. Peter’s, he calculated,
used slightly more than 111 million cubic Roman palms of stone. (For reference, a Roman
palm is equivalent to .73 feet or .22 meters.)
After deciding, for reasons never explained, that the average cost to move, shape, and
place a cubic palm of stone was 32½ baiocchi (that is, about a third of a scudo), and after
compiling the additional costs of the marble columns and decorative finishes, Fontana concluded
that St. Peter’s Basilica had cost 46,800,498 scudi.
Leaving aside the accuracy of this estimate, let’s try to put 46.8 million scudi in context.
In the mid-sixteenth century, one scudo could buy 28 chickens, 50 kilograms of flour, or
a month’s rent in a cheap Roman apartment.
In the same period, a master builder earned about 5 scudi a month, and the architect of
St. Peter’s was paid 50 scudi a month. For comparison, the great composer Palestrina
earned 8 scudi a month as choirmaster of St. Peter’s, which was about as much as a junior
professor at the University of Rome.
Focusing on artists, Caravaggio was paid between 150 and 400 scudi for most of his paintings.
A century earlier, Raphael was paid 1200 scudi for each of the frescoes in the Vatican Stanze,
and Michelangelo earned the equivalent of about 3,300 scudi for painting the ceiling
of the Sistine Chapel.
When he died in 1564, Michelangelo’s life savings were found to consist of 8,400 scudi.
The famous poetess and courtesan Tullia d’Aragona, by contrast, died with little more than her
prized pearl necklace, which was auctioned off for 40 scudi.
In 1536, King Henry VIII reportedly promised 50,000 scudi to any assassin who managed to
kill Cardinal Reginald Pole (five men tried; none succeeded). At that time, 50,000 scudi
was equivalent to the annual income of Rome’s wealthiest merchants and cardinals. The annual
income of the pope himself was roughly 2,500,000 scudi.
To judge from these numbers, the construction of St. Peter’s cost about as much as 19
years of the Papal States’ annual income, 936 high-profile assassinations, 15,600 Sistine
Chapel ceilings, or 3,900,000 years of rent in a cheap Roman apartment. Before we translate
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Back to our topic. It is difficult to convert premodern currencies into dollars, since the
purchasing power of money and the relative values of goods and labor vary with time and
place.
One method of comparison is based on bullion prices. Since scudi issued by the Papal States
weighed 3.38 grams, and had a fineness of 22 carats, they contained about 3.08 grams
of gold. At today’s prices, a gram of gold is worth $61.92, which would make the gold
in one scudo worth $190.71. But this isn’t especially helpful, not least because the
value of the modern dollar is independent of gold prices.
Another method of comparison focuses on wages. In late sixteenth-century Florence, an unskilled
construction worker earned about 33 scudi a year. Wages were slightly higher in Rome,
where the annual income of an unskilled laborer seems to have averaged around 40 or 50 scudi.
In modern America, the average annual income of an unskilled construction laborer is about
$35,000. If we take $35,000 as the equivalent of 50 scudi, we get a value of $700 for one
scudo. At $700 a scudo, the construction of St. Peter’s Basilica cost the equivalent
of $32,760,348,600.
This, obviously, is a lot of money – far more than is attested for any modern church.
Cologne Cathedral, completed in the mid-nineteenth century for the equivalent of about $1.5 billion,
might be the closest parallel.
The Burj Khalifa in Dubai, the world’s tallest building, was completed in 2010 at a reported
cost of $1.5 billion – $2.1 billion now, adjusted for inflation. SoFi stadium in California,
the most expensive sports venue ever built, was completed for $5.5 billion, and the Apple
campus in Cupertino cost $5 billion. Among all modern buildings, only a few nuclear power
plants and the recent expansion of the Great Mosque of Mecca approach or exceed my estimate
for the total cost of St. Peter’s.
Turning to pre-modern buildings, an especially intriguing comparison is the Taj Mahal, which
was built around the same time as St. Peter’s. Although the Taj Mahal is a smaller and simpler
structure than St. Peter’s, the decoration – and especially the interior, which is
inlaid with semi-precious stones – is incredibly elaborate.
At the time of the Taj Mahal’s construction, an unskilled laborer earned something like
20 silver rupees a year. Using the same method of conversion that we applied to St. Peter’s
gives a purchasing power equivalent of $1,750 for a Mughal silver rupee. Depending on the
source you read, the Taj Mahal is said to have cost 41.8, 50, or 91.7 million silver
rupees. That gives a cost of construction ranging from 7.3 to 16 billion modern dollars
– in other words, between about a quarter and half of the cost to build St. Peter’s
Basilica.
So – having contextualized the original expense of St. Peter’s Basilica, let’s
consider how much it would cost to build an exact replica of the church today. Since I
have no expertise in this sort of thing, I sent out an appeal to my subscribers, asking
anyone with professional experience in estimating the cost of large masonry structures to contact
me. Eight intrepid subscribers responded; and two of them went the distance and provided
full estimates.
I gave these bold volunteers a few specifications. The replica of St. Peter’s would be built
with modern technology but the same materials as the original. It would be constructed in
America – near, but not at the center, of a major city. The land would be donated. The
estimators were free to determine the region in which their replica would be built, and
to specify whether or not the labor would be unionized.
The first estimate came from EJ, a project engineer who specializes in masonry construction.
EJ’s estimate does not include the Baldacchino or Throne of Peter, two bronze structures
so large and unique that they have no modern parallels. Nor, due to time constraints, could
it take account of the crypt or the staircases that give access to the dome.
EJ placed the replica just outside New York City, in Yonkers. Even assuming a level site,
the foundation and wall core together were the biggest expense, costing something like
$9.2 billion, thanks to the labor costs of laying so many blocks. The great dome – covered
with lead and built (like the original) from brick, would cost about $320 million. The
colossal piers beneath the dome would require $178 million. The smaller domes, also brick,
would add $20 million more.
The travertine cladding of the exterior would set the builders back a whopping $1.6 billion.
The columns, pilasters, and statues of the exterior could be replicated – assuming
that they could be shaped by machine, and not sculpted by hand – for $1.1 million.
The five bronze doors of the façade would cost nearly $23 million.
For the marble revetment of the interior, $75 million, for marble columns and statues,
$11 million. For the marble floor, $18.5 million; for the mosaic and plastered ceilings, $126
million. Scaffolding alone would cost more than $26 million, and the roof tens of millions
more.
EJ estimated that, even without the Baldacchino and the other omitted details, a replica of
St. Peter’s Basilica in Yonkers would cost $11.6 billion, and take 27 years to build.
The second estimate, submitted by a heavy construction estimator who wishes to remain
anonymous, was lower. This estimator believed that, with the use of modern methods and despite
the expense of labor, the basic construction costs of a replica of St. Peter’s would
be only about $891 million – roughly as much, he noted, as a modern supertall skyscraper.
To these costs would have to be added the costs of design, which – thanks to the complexity
of the building – would be very substantial, coming in at about $151 million. Construction
management would add $178 million. The costs of inspection would total $44 million.
Including all other expenses – such as permitting ($8.9 million), surveying ($13 million), and
safety measures ($22 million) – he believed that a modern replica of St. Peter’s could
be constructed for a total cost of $1.5 billion.
So, to tally up all the big numbers in this video: St. Peter’s Basilica is estimated
to have cost 46.8 million scudi, which can be equated to $32.7 billion – roughly as
much as the most expensive modern buildings. Our two estimates for the cost of building
an exact replica of the church came in at $1.5 and $11.6 billion – as much, respectively,
as a supertall skyscraper or a large nuclear power plant.
I have a new book: Insane Emperors, Sunken Cities, and Earthquake Machines: more frequently
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