Good morning.

Today, a hole in a cathedral roof that sat open to the sky for over a hundred years… and the man who finally closed it, without a single piece of scaffolding.

Let’s begin.

The Man Who Built Without Scaffolding

Filippo Brunelleschi — The Dome of Florence Cathedral, 1436

The dome planned decades earlier called for a span of over 43 metres… wider than the Pantheon in Rome, wider than anything built since antiquity. There wasn't even enough timber left in Tuscany for the wooden scaffolding a dome that size would normally need.

On 19 August 1418, city officials announced a competition. Whoever solved the dome would win 200 gold florins and the job of a lifetime.

Filippo Brunelleschi (1377–1446) entered. He was a trained goldsmith, not an architect. In 1401 he had lost a famous competition of his own, for the bronze doors of the city's Baptistery, to a rival named Lorenzo Ghiberti (1378–1455). Stung, Brunelleschi left for Rome, where he spent years studying the ruins of the Pantheon, quietly working out how the Romans had built a dome that still stood after 1,300 years.

Now he was back, with a claim that sounded like madness: he could raise the dome with no scaffolding at all.

According to a story told by the 16th-century writer Giorgio Vasari, the judges demanded he explain his method before they'd hire him. Brunelleschi refused, worried a rival would steal the idea. Instead, he challenged the room to stand an egg upright on a marble table. One by one, they tried and failed. Brunelleschi picked up the egg, cracked its base gently on the table, and stood it up. The judges complained that anyone could do that once they'd seen it done. He is said to have replied that they'd say the same about his dome, once it was built. Historians doubt the story happened exactly this way… but it captures something true about the man.

He won the commission in 1420. Just to keep him honest, the city also hired Ghiberti as his co-supervisor, on equal pay. Brunelleschi solved that problem too: he faked an illness and let Ghiberti try running the site alone. Ghiberti, with no real plan of his own, floundered within weeks, and by 1423 Brunelleschi was back in sole charge.

Here's what four million bricks and sixteen years of work eventually produced.

Filippo Brunelleschi, the Dome of Florence Cathedral (Santa Maria del Fiore), completed 1436.

Here's what you're looking at. The dome is actually two domes, one nested inside the other. The inner shell carries the real structural weight. The outer shell, thinner and lighter, exists mainly to give the building its iconic profile and to shed rain. Between the two, hidden from anyone standing on the cathedral floor, run a network of stone ribs, walkways, and stairs.

Now picture the actual bricklaying: one course at a time, in a rising, roofless octagon eighty metres off the ground. A circular dome can support itself as it goes, because each ring of brick acts like a small stone arch, squeezing itself tight. But Florence's dome isn't circular. It's octagonal, with eight long, flat-ish sides. On those flat stretches, ordinary horizontal bricklaying would simply slide outward mid-construction, wet mortar and all.

Brunelleschi's fix was to lay the bricks in a herringbone pattern… alternating diagonal courses, called spinapesce, "fishbone," in Italian. Every so often, a line of bricks stands on end instead of lying flat, wedging itself against its neighbours like a keystone. It let each ring lock itself into place the moment it was laid, with nothing underneath to hold it up.

For almost six hundred years, nobody could fully explain, in the language of modern engineering, why it worked. It wasn't until a 2020 study by researchers at Princeton and the University of Bergamo that anyone modelled the physics precisely: the diagonal bricks act as a spiralling double helix of support, redirecting the dome's weight sideways into the ribs instead of letting it slide. Brunelleschi had worked this out by instinct, four centuries before anyone had the mathematics to prove he was right.

In other words: what looks like decoration up there is structural genius, hiding in plain sight in the brickwork.

Not everything on the outside got finished to plan. By 1515, workers had completed one marble balcony around the base of the dome's drum, on the southeast side, and asked Michelangelo, by then the most trusted eye in Florence, what he thought. He is said to have compared it to a cage for crickets. Work stopped immediately. Five hundred years later, seven of the eight sides are still bare brick.

I climbed the 463 steps myself a few years back… a narrow, hot, one-way stairwell squeezed between the two shells. About halfway up, the herringbone brickwork is close enough to touch. I didn't know what I was looking at then. I just thought it looked oddly deliberate for something so far off the ground, where almost nobody would ever see it. Now I know why.

Brunelleschi never saw the very top finished. He died in 1446, ten years after the dome's consecration, while the lantern crowning it was still under construction. His friend Michelozzo completed it by 1461. In 1469, the sculptor Andrea del Verrocchio… whose workshop trained a young Leonardo da Vinci… added the gilded copper ball and cross at the very peak.

Vasari, writing a century later, needed a word for what he thought had happened in Florence during Brunelleschi's lifetime: a return, after centuries of decline, to the ambition of the ancient world.

Florence, 1418. A hole in a roof, an out-of-work goldsmith, and an idea nobody else was willing to risk… four million bricks later, it's still standing, six hundred years on, waiting for anyone willing to climb up and look closely enough to see how.

Three Things Worth Knowing

Connoisseur's Diary

Worth Seeing This Week

The best way to see Brunelleschi's engineering secret in person is to climb it. The Brunelleschi Pass takes you up 463 steps, through the narrow passage between the dome's two shells, where the herringbone brickwork is close enough to touch.

Where: Piazza del Duomo, Florence; the Dome climb enters from Porta della Mandorla, on the cathedral's north side.  Tickets: the Brunelleschi Pass costs €30 for ages 15+, €12 for ages 7–14, free under 7, and also includes the Bell Tower, Baptistery, Opera del Duomo Museum, and Santa Reparata crypt, valid three days.  Insider tip: the Dome climb requires a mandatory timed reservation that often sells out two to three weeks ahead, so book before you land in Florence.  Book at tickets.duomo.firenze.it →

Worth Reading

Brunelleschi's Dome — Ross King (2000). A tight, propulsive account of the sixteen years it took to raise the dome, and the volatile genius behind it.

Lives of the Artists, Vol. 1 — Giorgio Vasari (1550). The source of the egg story, and of the word "rinascita" itself, told by a writer who knew Michelangelo personally.

The Divine Comedy — Dante Alighieri, trans. Robin Kirkpatrick (2014 edition). The poem Florence was already picturing itself in, a century before Brunelleschi gave it a dome to match.

Test Your Knowledge

Enjoyed testing yourself? Write in and tell me which one got you — I read every reply.

That's all for today.

Next up: a philosopher who decided to doubt absolutely everything… including whether his own hands were real.

In good taste,

Charles T. Mayfair

Editor, Connoisseur Daily