{"id":61264,"date":"2026-08-27T16:20:07","date_gmt":"2026-08-27T14:20:07","guid":{"rendered":"https:\/\/www.florenceforanyone.com\/?p=61264"},"modified":"2026-08-27T16:21:35","modified_gmt":"2026-08-27T14:21:35","slug":"brunelleschis-dome","status":"publish","type":"post","link":"https:\/\/www.florenceforanyone.com\/en\/brunelleschis-dome\/","title":{"rendered":"Brunelleschi’s Dome: how it was built and what to see today"},"content":{"rendered":"\n

The time when it is best to arrive at Cathedral Square is early in the morning, before the organized groups arrive:if you arrive where Via dei Calzaiuoli ends you will be able to observe the entire dome simply by raising your head.<\/p>\n\n\n\n

What we see today is the solution to a problem that for almost a century had not had one: Santa Maria del Fiore.<\/strong> It was designed, at the end of the fourteenth century, with a dome larger than any other ever built up to that time: approximately 45 meters<\/strong> in diameter at the base. The technical problem was real: a structure of those dimensions could not be built using the wooden ribs normally used; there simply wasn’t enough wood available, nor was there a structure capable of supporting that weight during construction. For this reason, for several decades, the church remained without a roof above the intersection of the naves.<\/p>\n\n\n\n

A solution came in 1418<\/strong>, when the Wool Art<\/strong> (the corporation that financed and supervised the works of the Duomo)announced a public competition to find someone who could solve the problem. Filippo Brunelleschi<\/strong>, who was not an architect by training but a goldsmith and sculptor, won this competition.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

In this article, I reconstruct how he arrived at that solution, how the dome was actually built, and what to see today, from below and up inside the structure.<\/p>\n\n\n\n

The 1418 competition<\/h2>\n\n\n\n

The Arte della Lana tender asked for something very specific: a model demonstrating how to cover the dome without using wooden ribs for support during construction. And here is the crux of the matter, as well as the reason why the church remained uncovered for decades.<\/p>\n\n\n\n

Domes of that size were traditionally built by supporting the fresh masonry with a wooden framework that held the weight until the mortar dried. For the dome of Santa Maria del Fiore, such a framework would have required more wood than Tuscany could provide, as well as supporting structures that would have filled the entire nave for years.<\/p>\n\n\n\n

Several master builders and engineers, both Italian and foreign, participated in the competition. Among them was Lorenzo Ghiberti<\/strong>, already established after having won the competition for the second door of the Baptistery a few years earlier. Brunelleschi presented a model(unfortunately lost today, only descriptions remain in the sources of the time) who proposed to build the dome double cap<\/strong>, supporting each layer of masonry with the newly completed one underneath, without the need for ground reinforcement.<\/p>\n\n\n\n

The Opera del Duomo was not entirely confident: it appointed both Brunelleschi and Ghiberti as master builders of the factory, with equal salaries, despite Brunelleschi having presented the technical solution. Ghiberti retained the role for several years, although contemporary sources disagree on how much technical work he actually contributed to the dome’s construction, unlike Brunelleschi, who was its designer.<\/p>\n\n\n\n

One of the most told stories about this period is the egg anecdote.<\/strong> During the selection process, the competing architects were asked who could make an egg stand upright on a smooth surface, and only Brunelleschi succeeded by pressing its base onto the table.<\/p>\n\n\n\n

How do you build a dome without reinforcement?<\/h2>\n\n\n\n

Brunelleschi’s solution is based on two specific technical ideas.<\/p>\n\n\n\n

The first is the double cap.<\/strong> The dome is not a single structure, but two concentric shells, a thicker inner shell (for load-bearing purposes) and a thinner outer shell (for cladding and weather protection), connected by ribs and cavities. This reduces the overall weight compared to a solid dome and creates an empty space between the two shells, which, not surprisingly, is now walkable. In fact, inside there is the staircase that is still climbed today to reach the lantern.<\/p>\n\n\n\n

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The second is the herringbone masonry<\/strong> (in historical Italian, “herringbone”): the bricks are not arranged in continuous horizontal rows, but in inclined groups that alternate directions, interlocking like the tiles of a fishbone. Each ring of bricks supports itself while the mortar is still fresh, transferring the weight towards the eight ribs<\/strong>(the white stone ribs that can still be seen today running along the eight red segments of the dome, from the outside) instead of downward. It is precisely this mechanism that eliminates the need for wooden ribs: each layer of masonry supports itself and the next as the construction site rises.<\/p>\n\n\n\n

There is a third element, less visible but equally important: chains<\/strong> (horizontal rings in stone, wood and iron, inserted at different heights within the structure)which counteract the outward thrust that a dome of that size naturally exerts on its base. Without this containment system, the weight of the dome would have risked pushing the drums on which it rests outward, potentially causing them to open and collapse.<\/p>\n\n\n\n

To build all this, Brunelleschi also had to solve a very practical problem: how to lift tons of bricks, stone, and materials almost one hundred meters high, for years, without ever interrupting the construction site. <\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

He himself designed some of the machines used to hoist the materials, including an ox-powered winch capable of lifting enormous loads and, more importantly, reversing the direction of rotation without disconnecting the animals: an ingenious and novel solution, which saved precious time with each single lift, repeated thousands of times during the construction site.<\/p>\n\n\n\n

Twenty years of construction<\/h2>\n\n\n\n

Work on the dome itself began in 1420<\/strong> and they concluded, for the wall part, in 1436<\/strong>: sixteen years of uninterrupted construction, during which Brunelleschi remained the designer and technical coordinator, solving the problems that arose from time to time. This includes numerous clashes with Ghiberti, who for years held a responsible role equal to his, before being progressively excluded from the most important technical decisions.<\/p>\n\n\n\n

The dome was consecrated in 1436<\/strong> by Pope Eugene IV, but it was not yet completely complete: it was missing the flashlight<\/strong>, the crowning structure at the top of the dome. A competition was held for that too, in 1436, which Brunelleschi won once again. But this time he did not live to see it finished: he died in 1446<\/strong>, when the lantern was just started. It was completed in 1461<\/strong> by his collaborators, who followed the original project.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

There’s another very amusing anecdote about the start of construction. Filippo Brunelleschi’s undertaking began with a simple and curious gesture: a breakfast offered to the more than 300 construction workers, including bread, wine, and melon.<\/p>\n\n\n\n

What to see today<\/h2>\n\n\n\n

Today you can climb inside the dome, walking through the space between the two shells that Brunelleschi designed six hundred years ago: they are 463 steps<\/strong>, up a narrow staircase that leads to the base of the lantern. It’s best to book in advance, as places to climb are limited and sell out quickly during peak season.. Also put taking into account that, once you start the climb, there is no way back unless you reach the top: the path is one-way.<\/p>\n\n\n\n

Along the way up, you can see the herringbone masonry described above up close: it’s one of the few points where the dome’s construction technique, usually hidden, becomes visible to the naked eye. Before reaching the base of the lantern, you also pass the level of the matroneo<\/strong>, from which you can observe the Last Judgement<\/strong>, the fresco that covers the interior of the dome, begun by Giorgio Vasari in 1572 and completed after his death by Federico Zuccari.<\/p>\n\n\n\n

Once you reach the top, at the base of the lantern, a view opens up over all of Florence: the rooftops of the historic center, the Arno River, and the hills surrounding the city. It’s the same spot from which, for centuries, the dome was the tallest building in the city, among other things by choice, since no other building could be built higher than the dome of the Cathedral.<\/p>\n\n\n\n

Because it is still unique<\/h2>\n\n\n\n

When it was completed, the dome of Santa Maria del Fiore was the largest ever built in masonry, without the use of temporary wooden frameworks to support it during the work. In a technical solution that, at the time, no one else knew how to replicate.<\/p>\n\n\n\n

Brunelleschi’s method was never written down in a detailed treatise: it was partly reconstructed in the following centuries by observing the structure itself.<\/p>\n\n\n\n

It is a building that can still be seen, touched and climbed, exactly as the Florentines of the fifteenth century saw it, with the difference that today, once you reach the top, you know exactly how you got there. August 7, 1420, therefore, was not just the beginning of a construction site: it was the beginning of one of the most extraordinary architectural challenges of the Renaissance, destined to transform a seemingly impossible idea into reality.<\/p>\n","protected":false},"excerpt":{"rendered":"

For nearly a century, the dome of Santa Maria del Fiore remained an unsolved problem: both the technique and the materials needed to build it were lacking. I’ll tell you how Filippo Brunelleschi found the solution in 1418, how the dome was actually built, and what to see as you climb its 463 steps to the lantern.<\/p>\n","protected":false},"author":5,"featured_media":61250,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"Brunelleschi's Dome: History of its Construction and What to See Today","_seopress_titles_desc":"How Brunelleschi built the dome of Santa Maria del Fiore without wooden ribs and what to see today as you climb the 463 steps to the lantern.","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"62","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"footnotes":""},"categories":[66,62],"tags":[],"class_list":["post-61264","post","type-post","status-publish","format-standard","has-post-thumbnail","category-fun-facts-and-folklore","category-history-of-florence"],"meta_box":[],"_links":{"self":[{"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/posts\/61264","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/comments?post=61264"}],"version-history":[{"count":0,"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/posts\/61264\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/media\/61250"}],"wp:attachment":[{"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/media?parent=61264"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/categories?post=61264"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.florenceforanyone.com\/en\/wp-json\/wp\/v2\/tags?post=61264"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}