How the World’s Biggest Dome Was Built: The Story of Filippo Brunelleschi and the Duomo in Florence


Even if Florence didn’t represent the absolute pinnacle of human civilization at the end of the thirteenth century, it had to have been a strong contender for the position. What the city lacked, however, was a cathedral befitting its status. Hence the construction, which commenced in 1296, of just such a holy structure, in accordance with ambitious plans drawn up by architect Arnolfo di Cambio. But when di Cambio died in 1302, work came more or less to a stop for nearly half a century. Construction resumed in 1344 under Giotto, whose own death three years later left the project to his assistant Andrea Pisano, who was himself succeeded by Francesco Talenti, Giovanni di Lapo Ghini, Alberto Arnoldi, Giovanni d’Ambrogio, Neri di Fioravanti, and Andrea Orcagna.

None of these architects, however astute, managed to finish the cathedral: in 1418, it still had a gaping hole on top where its dome should have been, and in any case no viable design or engineering procedure to construct one. “So they had a competition, and everybody was invited to submit their projects,” says Youtuber Manuel Bravo, who tells the story in the video at the top of the post.

Enter the sculptor Filippo Brunelleschi, who declared, in effect, “I can do it. I can build you the dome. And what’s more, I can build you the dome without coins or earth.” That last was a reference to an earlier architect’s suggestion that the dome under construction be supported with a mound of dirt filled with money, so peasants would gladly volunteer to cart it away after completion.

Brunelleschi’s considerably more elegant idea was inspired by the ruins of antiquity, not least the Pantheon, which then boasted the largest dome ever built in Europe, discussed by Bravo in a previous video. In this one he breaks down the ingenious techniques Brunelleschi used to outdo the Pantheon, and without using a temporary supporting structure of any kind. Instead, he incorporated ring-like elements “tying the dome from outside, as if they were belts like the ones we wear,” as well as “a particular kind of brickwork, a pattern with a series of spiral ribs” which “allowed them to lock together the bricks that were placed horizontally.” The result, a structure “completely self-bracing in all its phases of construction,” has stood firmly since 1469 as, quite literally, a crowning glory: not just of the Duomo, but of Florence as well.

Related content:

How Filippo Brunelleschi, Untrained in Architecture or Engineering, Built the World’s Largest Dome at the Dawn of the Renaissance

How to Build Leonardo da Vinci’s Ingenious Self-Supporting Bridge: Renaissance Innovations You Can Still Enjoy Today

The Life & Times of Buckminster Fuller’s Geodesic Dome: A Documentary

The Beauty & Ingenuity of the Pantheon, Ancient Rome’s Best-Preserved Monument: An Introduction

The History of Western Architecture: A Free Course Moving from Ancient Greece to Rococo

Free Course: An Introduction to the Art of the Italian Renaissance

Based in Seoul, Colin Marshall writes and broadcasts on cities, language, and culture. His projects include the Substack newsletter Books on Cities, the book The Stateless City: a Walk through 21st-Century Los Angeles and the video series The City in Cinema. Follow him on Twitter at @colinmarshall or on Facebook.



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