The masonry type used by Brunelleschi, herringbone, was not entirely novel. Romans had used it before, but for decorative purposes only. What is new is that Filippo used vertical stones, with the next stone joining horizontally, to anchor the nine horizontal rings and make them sturdier. What’s more, the downward force is absorbed much better this way.
In 2012, during the expansion of the Museo Opera dell’Duomo, an important discovery was made. A small dome was discovered in a parking garage during the excavations. The revolutionary masonry patterns in the dome of the Duomo were used here as well. Brunelleschi presumably built this to convince the commission, but also the masons that this type of masonry would produce sturdy walls.
Brunelleschi did not leave any documents detailing the construction of the dome. Nonetheless, a parchment document was uncovered with a drawing and text by Giovanni di Prato. This document, written five years into the construction of the dome, has Giovanni providing an account of the rope lines and what they were attached to. Brunelleschi used the ropes to accurately check each of the eight walls so they would line up perfectly at the top. In the text next to the drawing, Giovanni presents a sharp critique of Brunelleschi and he predicts the dome will collapse. See also the video about the rope lines and the drawing with text by Giovanni Di Prato.
The dome was completed in 1436, but the octagonal opening at the top still needed its crown.
‘A similar ‘tender’ was issued for the construction of the lantern, inviting each artist to submit a mode.16 The best and most beautiful design would then be carried out. For a third time, Brunelleschi had to first enter a competition while his rival Ghiberti, after completing his first door for the Baptistery, was given the immediate assignment in 1424 for what was later called the “Paradise Gates”. “Filippo must have been insulted more deeply by the fact that one of his fellow competitors was but a humble plumber, and another was a woman: the biggest insult of them all.” Ross King says. The assistant and carpenter, Antonio di Ciaccheri Manetti (not Manetti the Biographer) also submitted a model. His model showed he had committed plagiarism. He had largely copied the design of Filippo. The other artists were united in their admiration of Brunelleschi’s design.
But they did feel he made one mistake: how on earth would you move from the lantern to the globe with the large cross on top of it? According to Vasari, Filippo had the perfect retort. He removed a piece of wood from his design and showed the stairs to the globe. ‘[…] in the form of a hollow blow-pipe, having on one side a groove with rungs of bronze, whereby one ascends to the top, putting one foot after another. Once arriving at the top, right after leaving the stairs and standing next to the lantern; you will see a small opening to the left that is closed off with mesh. Looking into it, you will see the stairs and rungs Vasari is talking about. One thing becomes clear, these stairs were definitely meant for smaller people.
Inside the Opera del Duomo, which is now a museum, we will still be able to see Brunelleschi’s wooden model next to his death mask. Brunelleschi won the battle. The lantern required an immense amount of marble. Some marble blocks weighed up to an impressive two-and-a-half tonnes. Many remained sceptical about the amount of marble required, located on the square near the Duomo, which had to be placed atop the dome as a crown. Could the dome handle the immense total weight of over half a million kilos? Brunelleschi, who died shortly after construction of the lantern started, left an express statement in his will:
“[…] that it was to be constructed according to his model and written instructions; because otherwise, he emphasised, the entire work would collapse, as it was ribbed into pointy, conical arches, with another weight having to be placed on top to add to the overall sturdiness.” Translated from: Giorgio Vasari ‘De Levens van de grootste schilders, beeldhouwers en architecten’ Deel I pp. 179 – 180
Crowning the lantern
According to Vasari, it was Andrea del Verrocchio who placed the crown after Brunelleschi’s death.
Vasari writes about it in his Vita about Andrea as follows:
“Afterwards, the building of the Cupola of S. Maria del Fiore having been finished, it was resolved, after much discussion, that there should be made the copper ball which, according to the instructions left by Filippo Brunelleschi, was to be placed on the summit of that edifice. Whereupon the task was given to Andrea, who made the ball four braccia high, and, placing it on a knob, secured it in such a manner that afterwards the cross could be safely erected upon it; and the whole work, when finished, was put into position with very great rejoicing and delight among the people. Truly great were the ingenuity and diligence that had to be used in making it, to the end that it might be possible, as it is, to enter it from below, and also in securing it with good fastenings, lest the winds might do it damage.” Translated from: Giorgio Vasari, ‘De Levens van de grootste schilders, beeldhouwers en architecten Van Cimabue tot Giorgione’, Contact, Amsterdam, 1990 Deel I blz.269 (original edition 1568).
The dome: a new style or just gothic?
The ‘German school’ introduced the following intriguing thesis:
“The double shell, the shape and size were determined ten years before Brunelleschi’s birth, so in 1367. The famous construction that is usually marked as the advent of a new period, the Renaissance, has nothing to do with it” Heinrich Klotz, ‘Filippo Brunelleschi The Early Works and the Medieval Tradition’, Rizzoli, New York 1990 p. 78.
Still, Brunelleschi’s dome is unique; as his dome clearly rises above the pitched roof of the nave. What’s more, Brunelleschi succeeds in having the dome connect naturally to the underlying structure. The same cannot be said for the domes in Pisa or Siena. Domes that are hardly convincing. They cannot be clearly seen from the outside (except here, but from above) and their connection to other building components is rather forced. Dome support did succeed in Siena and Pisa, but at the expense of a clear and logical layout. In addition, Brunelleschi used gothic constructions, but several elements were completely novel. For instance, he did not use scaffolding from the ground up, he did not use aerial arches with buttresses and visible ribbing was mostly hidden away in the wall planes similar to the chapels in the apse of the Duomo. The circle of chapels that were planned prior to Brunelleschi were to provide the required counter-pressure for the dome. The answer to the above question thus has two parts according to Klotz: the dome is gothic in essence, but also contains a number of elements that can be seen as part of the Renaissance.
Leon Battista Alberti ‘Self-portrait’
To Alberti, one of Brunelleschi contemporaries, the dome was a true, unique masterpiece as can be read in his foreword to the Italian version of De Pictura:
“Who, no matter how proud or jealous, would not praise Flip [Filippo] at seeing this enormous construction that rises to the heavens, wide enough to cast a shadow over all citizens of Tuscany and built without buttresses or wood supports [scaffolding from the ground up], a work of art that, if I recall, was deemed impossible in our time, while the ancients might not even have been able to conceive of it?” Translated from: Alberti, ‘Over de schilderkunst’, (translation Lex Hermans, Intro and annotations Caroline van Eck and Robert Zwijnenberg) Boom, Amsterdam Meppel 1996 p. 62