Filippo Brunelleschi and his Dome

Carl Kruse Art Blog

By Asia Leonardi

Filippo Brunelleschi (1377-1446), architect and engineer, sculptor and painter, is universally considered the pioneer of the Italian Renaissance and the creator of an approach to architecture that would dominate the European art scene, at least until the end of the 19th century. Through a passionate study of antiquity that brought him several times to Rome starting from 1402, he reacted to the anti-classicism of late Gothic architecture and artistic culture, referring consistently to the language of the ancients and proposing new design systems based on modular structures. The keystone of this cultural and technical turning point was the invention of the vanishing point perspective in which the great technological tradition of Tuscan architects and masters was combined with the new trends of scientific thought, all converging towards the ever-increasing use of mathematical tools in the study of reality.

By unifying all orthogonal lines towards a single vanishing point, the scientific rules were built to objectively measure the decrease in depth of bodies inserted in space. The  Florentine artist was among the first to elaborate and use rules and numerical relationships in the architectural construction of space and figurative representation. And this, together with the effort to identify the geometric principles used to organize the reproduction and creation of space, was the basis of a return to antiquity.

Architecture was for Brunelleschi a tool for mathematical control of design. Classical architecture is understood as an example of the exact measurability of space, as a clear example of the concrete possibility of subjecting the whole substantial reality of architectural space to rigorous mathematical formulas.


With Brunelleschi, a new system of organization of the construction site and of construction work came about and the new social figure of the architect was born.

The architect was no longer a superintendent of works, endowed with equal dignity concerning workers to a large extent operating on an autonomous level concerning him, as was the case in the Middle Ages, but an intellectual, cultured, an updated figure, who conceived and prepared the project and the details of the building, to which the activity of the workers, artisans, and contractors engaged in the work had to be instructed.

It was the end of the ancient organization of building activity, which had supported and achieved the great Florentine, and more generally Tuscan urban expansion of the 12th and 13th centuries. In a new relationship with the client, the new artist, as was outlined in the Bruneschellian experience, was a well-defined figure in his individuality, who ventured into the field of artistic innovation with a new, freer and more secular spirit.

But the figure of Brunelleschi would still be unclear if we did not put him in his historical context, in his place, that is, in Florence at the height of its territorial expansion and closely linked to its republican institutions. In the first sixty years of the fifteenth century Filippo Brunelleschi, Masaccio and Beato Angelico, Donatello, Nanni di Banco, and Lorenzo Ghiberti, Paolo Uccello and Filippo Lippi, Leon Battista Alberti, Luca Della Robbia, and other artists lived and worked in Florence, all animated by the same effort of cultural transformation, all converging in outlining the contents of new art and a new artistic figure.

Why, we might ask, did this constellation of artists come together in Florence? The early Renaissance artists, like few other examples in history (and the comparison with the Athens of the 5th century BC, although abused, may be useful), was configured as the expression, in the work of artists, of a cultural renewal that affected the entire city.

Thus, the desire of the artists to revive the noble classical prototypes was linked to the fervor of literary and humanistic studies and above all to the investigation, the enhancement of the virtues of the ancients, to the awareness that they could relive – indeed, that they were living – in contemporary Florence.

The Search for Measures and Proportions: Inspiration From the Classic

The trip to Rome (between 1402 and 1404) with Donatello was decisive for the formation of Brunelleschi’s architectural ideas. While his friend was more interested in the still visible examples of ancient sculpture, Brunelleschi studied the proportion of buildings and construction techniques. From Rome he returned with the idea that the architect should invent the overall structure of the building in proportional terms: concentrate on those, as the value and beauty of the work depended on them, and abolish the superstructure of the decorative elements, so dear to Gothic architecture. The assumption of ancient orders served this purpose: to limit the structural and decorative uncertainty of the Gothic to a reduced and correlated case study, according to ancient rules. The distance between two columns, to give an example, does not determine the height of the pointed arch thrown above them but instead defines the height of a round arch that joins them and allows to proportion the measures of the base and those of the height of the arch. The column, the pillar, the pilaster, the entablature, the round arch were the indispensable ingredients of an architectural practice that had, as its primary purpose, the creation of modular structures and the geometric rationalization of the plans and elevations. This is the radical innovation of the architectural practice made by Brunelleschi, who gave concrete proof of it in the buildings, secular or ecclesiastical, entrusted to him by the Florentine public groups and, more rarely, also by some private clients.

 The Dome of Santa Maria del Fiore.

Brunelleschi’s meditations on radial harmony developed during a long gestation resulting in one of his most daring and complex projects, the very symbol of the Florentine Renaissance and one of his best-known works in the world: the Dome of Santa Maria del Fiore.

He was involved in it from 1417 until his death, through successive phases in which the various components of the colossal project were progressively developed: the huge converging caps raised in the void upwards, above the drum; the final lantern, keystone of the dome (completed around 1460, after the artist’s death); the dead stands, decorative elements but also buttresses of the formidable lateral thrusts caused by the large dome. Brunelleschi’s genius in this undertaking, as has been repeatedly noted, did not consist so much in the conception of the pointed arch shape of the dome, which was forced by objective requirements (for such dimensions it was not possible to think of using a hemispherical shape ), as in the ability to prepare the tools to complete the work (construction systems, machinery) and in the correct planning of the work phases.

Carl Kruse Art Blog - diagram

Problems Posed by Construction.

The conclusion of the large apse tribune of Santa Maria del Fiore, by Arnolfo di Cambio (1367), and the subsequent erection of the massive octagonal drum (1413) with its four meter-thick walls, had left open the difficult problem of completing construction of the cathedral through an enormous dome, already foreseen by the original Arnolfian project. The opening that was intended to be covered by the dome, almost forty-two meters in diameter, was slightly smaller than the largest dome of antiquity, the Pantheon.

Following the competition launched at the Opera del Duomo in 1418, the construction of the dome was entrusted to Brunelleschi and Ghiberti, who were proclaimed winners after their joint a model of the project. The work began in 1420 and with that also disagreements between the two artists, and in 1426 Brunelleschi found himself with sole responsibility, something new for him, of the direction of the works.

The great innovation he introduced in the construction of the brick dome, supported by eight large white ribs, was the use of a load-bearing structure in every major phase of the work. The choice was a must: at this distance above the ground, it was not conceivable to use wooden reinforcements (ribs), as the traditional technique required.

Project and Organization of Works.

By adopting a double cap, internal and external, Brunelleschi simplified and strengthened the construction, placing the external one, parallel to the first, on twenty-four supports raised above the segments of the internal dome. The external dome was designed for practical and aesthetic purposes, to better protect the building from water, and to make it appear, as the work of the cathedral demanded, more magnificent and spacious.

It was up to Brunelleschi to think of the mechanical devices necessary to solve the complex problems of installation. For example, to lift the building material on the scaffolding he provided platforms for the workers; he even designed special boats for the transport of marble and bricks along the Arno. He designed every aspect of the dome covering, a first in the history of modern architecture, the position of sole manager.

Religious Significance and Earthly Significance.

After sixteen years of intense work, the dome was consecrated on 25 March 1436 by Pope Eugene IV. From a symbolic-religious point of view, it represented the triumphal crown of the Virgin to whom the Florentine cathedral was dedicated. But far more important was the earthly, social, and political significance of the work. Emblem of a city that had expanded its borders, the dome rose, with its expanded volume, over the roofs of the medieval city, detaching itself from the underlying body of the basilica, demonstrating a new way of considering history and space. Admired from afar, against the background of the hills that surround Florence, the dome, for the essentialness of its lines, for the visual effect induced by the contrast between the red brick of the caps and the white curvilinear ribs, becomes the pulsating center of a large urban system; dominating the entire region. The effect it had on his contemporaries must have been great because, as Alberti wrote, it seemed to “cover all the Tuscan peoples with its shadow”. It is a work still linked to the spirit of the Gothic because it is based on the  calculation of structural forces in equilibrium, but the result of a new mentality as it redefines and re-proportioned the underlying building redesigns and subdues the surrounding area. However, it is a Renaissance work because, as the architectural historian Leonardo Benevolo wrote, it is the first “where the architect is not only a high-level consultant for a collective body of executors, but the only one responsible for the form, decoration, structure, and construction site organization”.

Carl Kruse Art Blog - Sketch of Dome


Construction Techniques of the Dome

The size of the dome that was to be built forced Brunelleschi to adopt new solutions to solve extremely difficult technical problems, also aggravated by the considerable height. The work was entrusted to him not because he had presented a particularly compellingly shaped dome model, but because he had provided a coherent work plan for its construction.

Brunelleschi found solutions to thousands of practical questions, capturing the wonder and admiration of his contemporaries. Vasari lists some of these measures: Brunelleschi had organized a lighting system for the stairs and corridors that run, at various levels, between the internal and external envelope of the dome and had placed the iron support points there to make it easier go up and walk through those tunnels; he had arranged the support points for the scaffolding of whoever, in the future, would have wanted to decorate the inner shell with paintings or mosaics, as in fact happened.

 He had designed an elaborate rainwater drainage system; on the outside, he had even provided for “holes and several openings, so that the winds break, and the vapors together with earthquakes could not cause damage”. He went to the kilns to check that he was supplied with flawless bricks; he chose the stones one by one, making sure they weren’t cracked. He provided the stonecutters with models in wood and wax, and even carving them in turnips, in order to show them how the joints were to fix one stone to another. Nor could he overlook the problem of the organization of work. When the construction site gradually moved to higher altitudes, Vasari writes again, “workers lost a lot of time in going to dinner and drink, and they suffered great discomfort due to the heat of the day. It was therefore established by Filippo the order that taverns should have been opened in the dome with the kitchens, and wine should have been sold; and so no one would left work, except in the evening; which was to their convenience”. But the workers needed solid scaffolding to work safely at such high altitudes. At the beginning of the work, when the dome wall was still almost vertical, the scaffolding was supported by beams inserted into the wall, both inside and outside the building: but lastly, given the strong inclination of the masonry, he had to think of a different system. Filippo Brunelleschi designed a scaffolding suspended in the void, located in the center of the dome, probably supported by long beams on platforms fixed at lower altitudes. these platforms were also to serve as warehouses for materials and work tools. Brunelleschi had to take steps to lift the heavy bricks to the height of the installation.

He partly used traditional machines, derived from the construction practice of Gothic cathedrals, but he had to invent new ones, applying the multiplier system, invented for the manufacture of watches, which was able to increase the effectiveness of the strength of winches and pulleys. In such machines, the engine was driven by a couple of horses. By walking in circles, animals could rotate a vertical shaft. This, in turn, impressed it on a horizontal shaft from which the ropes that supported the loads, fixed at a height to pulleys, rolled and unwound. In this way bricks and stones could rise and fall through a difference in height of tens and tens of meters.


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Contact: carl AT carlkruse DOT com
Other articles by Asia Leonardi focus on Maria Abramovic, Frida Kahlo and Forgotten Places.
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Author: Carl Kruse

Carl Kruse: Human. Being.

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