The involvement of Leonardo da Vinci (1452–1519) in the competition for the design of the dome (
Many aspects of architectural practice and management in the early modern period can be inferred from an evaluation of the involvement of Leonardo da Vinci (1452–1519) in the competition, in 1487, for the design of the
Giacomo Brogi (1822–1881),
Giacomo Brogi (1822–1881),
The erection of the dome of Milan Cathedral is documented in many written sources, most of which have been published, especially in the nine volumes of the
A re-reading of the competition for the dome of the Milan Cathedral in the context of the cathedral’s entire building history is presented here as a case study to illustrate different aspects of architectural practice and management of large building projects of the early modern period, together with some operative elements of Leonardo’s architectural activity. The intent is not to illustrate all the previous interpretations of Leonardo’s project for the lantern nor to analyse the extensive existing bibliography on these reconstructive hypotheses, elsewhere presented by the author. Rather, in addition to presenting a new hypothesis, it investigates the architect’s involvement in this project to better understand features and practices of the architectural (and building-site) world of his time, drawing attention to the building ‘process’.
From the beginning of the cathedral’s construction in 1386, the deputies of the Veneranda Fabbrica del Duomo di Milano (Veneranda Fabbrica), the administrative body that oversaw the building’s construction and subsequent maintenance, called upon the very best designers for such an ambitious project. Over the years, this body appointed numerous architects from all over Europe, formed many commissions, and launched several competitions for the design and the construction of both the entire cathedral and its different parts and details, such as the elevation of the building and the design of the large capitals of the nave at the end of fourteenth century, or the dome at the end of fifteenth century. This consolidated system, which included numerous meetings and consultations with experts and took place almost continuously throughout the history of the building, undoubtedly slowed down the decision-making process. However, this system was a widely used
The competition of 1487 for the design of the
In Leonardo’s famous letter of 1485–1486 to Ludovico Sforza, called il Moro, the regent of the duchy of Milan, Leonardo celebrates his own expertise as a (military) engineer and architect.
What were Leonardo’s preliminary steps in approaching the design of the
We have some evidence that demonstrates how, armed with curiosity, Leonardo collected information to become familiar with the building site, its previous history, and the proposals of other masters involved in the competition. His use of sheets from old accounting books shows that he had close contacts with the administrative body of the cathedral in those years. There are many examples of his reuse of sheets from old accounting books of the Veneranda Fabbrica, such as the fragments Windsor 12476v with a drawing of an old man, dated about 1487, which was part of
We have also the initial paragraph of a Leonardo’s letter about the
Leonardo’s presence on or around the building site is also testified by several drawings in his manuscripts. On folio 10v of the Paris
Paris, Institut de France, Leonardo da Vinci,
Milan, Archivio Storico civico di Milano, Biblioteca Trivulziana, Leonardo da Vinci,
By carefully studying Leonardo’s drawings, we can also understand how he began the design process. Several of his manuscript codices contain quickly traced drawings for numerous possible design solutions for the
Milan, Archivio Storico civico di Milano, Biblioteca Trivulziana, Leonardo da Vinci,
Scrolling through the pages of Leonardo’s very small format notebooks, one can discover many extremely tiny and schematic plans of the dome, executed quickly with single strokes to represent walls and buttresses. Their variety suggests that the artist was experimenting simultaneously with very different types of solutions, probably still at the beginning of the design process. It is even possible that they date to before he entered the competition, perhaps late 1486, when the German chief architect Giovanni Nexemperger (Hans Nexemperger, from Graz) left both the building site and Milan (see
Once the Veneranda Fabbrica had entrusted the project to the several architects involved in the competition, it funded the creation of wooden models of their different proposals. This was a standard procedure in the great Italian building projects of the early modern period, part of a long tradition that goes back to the Middle Ages. As in a two-stage design competition of today, the committee would have chosen the definitive models from among the many proposals. These would have been then compared, analysed, discussed, and reviewed. This process was also followed at the cathedral, for instance, with Stornaloco and Giovannino de Grassi at the end of fifteenth century, with Filarete in the 1450s, and Nexemperger in the 1480s.
Leonardo’s model was carried out by the
The well-known and enigmatic drawing in folio 850r of
Milan, Biblioteca Ambrosiana, Leonardo da Vinci,
Milan, Biblioteca Ambrosiana, Leonardo da Vinci,
Leonardo’s mastery in drawing and representational systems is well known. In addition to the impeccable perspective of his paintings, he developed conventions for scientific drawings that are still in use today, such as the ‘exploded’ view for machine illustrations, working on a ‘progressive definition of a specific method of representation technique’ that he would master by the early 1490s (
The two drawings, 851r and 850r, successive copies made using the
Given the characteristics of the drawings, it is possible that a collaborator executed both of them and these were then modified, corrected, and annotated by Leonardo. Unfortunately, even in this case information about possible collaborators is scarce. Apart from the carpenter Bernardino da Abbiate, who made the wooden model, we know nothing about Leonardo’s pupils or collaborators at the cathedral or in his workshop during the period of the dome commission.
Since the late 1970s, most scholarship has maintained that these drawings represent a project consisting of a double shell with a squared dome on the outside (
Reconstructive hypothesis of Leonardo da Vinci’s project for the dome of Milan Cathedral according to Frances Fergusson (
Reconstructive hypothesis of Leonardo da Vinci’s project for the dome of Milan Cathedral according to Jean Guillaume (
The solution on which Leonardo dwells the most and reproposes many times in his sketches is a dome with a shape similar to Brunelleschi’s structure for Santa Maria del Fiore in Florence: a raised, ribbed dome with a double shell on an octagonal plan.
The history of the Milan Cathedral, too, suggests this interpretation of Leonardo’s proposal. The Veneranda Fabbrica had determined that the cathedral should have an octagonal dome structure as early as the 1460s, under the oversight of Guiniforte Solari, and it is unlikely that this goal changed; only proposals engaging octagonal solutions appear to have been considered. After initially celebrating the idea of a squared
Reconstructive hypothesis of Leonardo da Vinci’s project for the dome of Milan Cathedral according to the author.
Moving to the final stages of the competition, we know that several dignitaries took part at the great plenary meeting of 27 June 1490, when the final project was approved in the official final report on the
Although Leonardo did not pass even the first round of the competition, the experience was galvanising for him, on both practical and intellectual grounds. The collaboration with other experts and the focus on technical aspects related to architecture prompted his continuing and abiding interest over the following years in the principles of statics. This curiosity about theorising general statics and engineering assumptions was already evident in the aforementioned letter that was intended to accompany his wooden model for the Milan Cathedral. In this note, Leonardo did not describe the project but rather wrote that it was necessary for the architect to know ‘the rules from which a correct building derives and where those rules came from’ and ‘the reasons that make the building endure, and the nature of the weight, and the will of the force, and the way in which they have to be woven and connected together’.
Stimulated by this experience, he continued to reflect on the issues raised by the
London, Victoria and Albert Museum, Leonardo da Vinci,
Madrid, Biblioteca Nacional de España, Leonardo da Vinci,
For Leonardo, however, ‘wisdom is the daughter of the experience’ (‘la sapienzia è figliola dela sperienzia’, from
He also conceived stone ‘chains’ and tenon-and-mortise masonry joints to increase the rigidity of the structure while involving other parts of the building to support the dome in addition to the four piers of the crossing. He repeatedly illustrated those techniques of tenon-and-mortise and tooth joints of stone blocks in the
Evaluating the competition for the design of the dome of Milan Cathedral enables us to retrace the different phases of the building-site administration, the design process, and the decision-making process of one of the largest Italian building projects of the early modern period. This research also reveals how for Leonardo the competition was his first opportunity to both engage in architectural design and study problems of statics and mechanics in depth. He observed the work of his colleagues as well as local building traditions and then reflected on these topics in graphic form in his notebooks. Drawing was a tool of understanding, reasoning, and conceiving while he actively searched for ideas and solutions in every facet of the world around him.
For the cathedrals of Siena and Florence, see for instance
I would like to thank Janna Israel for having revised my English with great generosity.
Other examples can be found in Windsor 12632v; 12634v (
The text is the following: ‘Signori padri diputati, sì come ai medici, tutori, curatori de li ammalati bisogna intendere che cosa è omo, che cosa è vita, che cosa è sanità e in che modo una parità, una concordanza d’elementi la mantiene e così una discordanza di quelli la ruina e disfà, e conosciuto ben le sopra dette nature, potrà meglio riparare che chi n’è privato. Voi sapete le medicine, essendo bene adoperate, rendon sanità ai malati. Queste bene adoperate sara[n], quando il medico con lo intendere la lor natura intenderà che cosa è omo, che cosa è vita, che cosa è complessione e così sanità. Conosciute ben queste, ben conoscerà il suo contrario. Essendo così, ben vi saperà riparare. Voi sapete le medicine, essendo bene adoperate, rendon sanità ai malati e quello che bene le conosce, ben l’adopererà, quando ancora lui conoscerà che cosa è omo, che cosa è vita e complessione, che cosa è sanità. Conoscendo queste, bene conoscerà i sua contrari. Essendo così, pi[ù] visino sarà al riparo ch’alcun altro. Questo medesimo bisogna al malato domo, cioè uno medico architetto, che ‘ntenda bene che cosa è edifizio e da che regole il retto edificare diriva e donde dette regole sono tratte e ‘n quante parte sieno divise e quale sieno le cagione che tengano lo edifizio insieme e che lo fanno premanente, e che natura sia quella del peso, e quale sia il disiderio de la forza, e in che modo si debbono contessere e collegare insieme e, congiunte, che effetto partorisc[h]ino. Chi di queste sopra dette cose arà vera cognizione, vi lascerà di sua rason e opera sadisfatto. Onde per questo io m’ingegnerò non ditraendo, non infamando alcuno, di saddisfare in parte con ragioni e in parte coll’opere, alcuna volta dimostrando li effetti per le cagioni, alcuna vol[t]a affermando le ragioni colle sperienze, con queste accomodando alcuna alturità de li architetti antichi, le pruove de li edifizi fatti e quali sieno le cagioni di lor ruina e di loro premanenzia eccetera. E con quelle dimonstrare prima del carico e quale e quante sieno le cagioni che danno ruina a li edifizi e quale è il modo della loro stabilità e premanenza. Ma per non essere plorisso a vostr’eccellenze dirò prima la invenzione del primo architetto del domo e chiaramente vi dimostrerò qual fussi sua intenzione, affermando quella collo principiato edifizio e facendovi questo intendere, chiaramente potrete conoscere il modello da me fatto avere in sé quella simmetria, quella corrispondenzia, quella conformità, quale s’appartiene al principiato edifizio. Che cosa è edifizio e donde le regole del retto edificare hanno dirivazione, e quante e quali sieno le parte appartenente a quelle. O io o altri che lo dimostri me’ di me, pigliatelo. Mettete da canto ogni passione’.
For the affirmed analogy between medicine and architecture (which was already used by Leon Battista Alberti and Filarete) and the reference to the 2nd-century Greek physician Galeno, see
All translations provided in the text are mine.
‘la ragion d’una volta, cioè il terzo del diametro de la sua camera’.
For the discussion of previous literature, see
For this proposal and the resulting dating of the drawings at 1488–1489, see
ASMi,
Later, he learned from Bramante about a drawbridge:
For the models carried out for Milan Cathedral, see
AVFDMi,
ASMi,
AVFDMi,
On these two drawings, see
Among others,
Elevations in orthogonal projection too are virtually absent in Leonardo’s repertory (
In the drawing the sectioned parts are not graphically distinguished from those in projection, and the different planes in which the elements are located are not easily recognisable, in particular the spatial direction of the lower arches. Here are some of the major doubts raised by the drawing: Are the pendentives present or any other transitional system connecting the dome to the four pillars of the crossing? Shouldn’t the turrets in the four corners be visible only on the outside of the dome shell, if this truly were a section in orthogonal projection? Where is the inclined element at the top right — generally interpreted as a flying buttress — positioned in space? Are the different stone chains in the lower part all positioned on the same plane? If, instead of a cross-section, there was a section made along one of the walls of the crossing (which is rather bizarre for a section anyway), as proposed by Fergusson (and then followed by Guillaume and Schofield), wouldn’t the shell be interrupted horizontally, as it is curved towards the observer out of the plane of section? Otherwise, one must suppose that the shell was flattened on the section plane. The elements that have been interpreted as inclined arches connecting the dome to the turrets shouldn’t be visible; and also, the indications about the turrets would result very inaccurate.
On the fixing of architectural representation system and orthogonal projection drawings in the early 16th century, see the seminal
To copy a drawing from another through the
Since the two drawings are of the same size and proportions, Fergusson (
On Leonardo’s assistants in Milan, see
Guiniforte Solari became architect of the Veneranda Fabbrica in 1459. His project for the dome was probably an octagonal structure resting on a system of decreasing arches in the corners instead of pendentives, in line with the dome of the Certosa di Pavia, built by Guiniforte himself, and with the Lombard traditions. After his death in 1481, the dome was demolished because of structural problems and other undefined defects. On this important episode, for which the archival records are extremely scarce, see
For the frequency in Leonardo’s sketches of this scheme, see
Reference to Brunelleschi as primary stimulus for Leonardo’s churches is present also in
General reflections on loading and breaking schemes of pointed and round arches can be also found in
‘Fondamento. Qui si dimosstra come li archi fatti ne’ lati dell’ottangolo spingano i pilastri delli angoli in fori, come si dimostra nella linia h c e nella linia t d, che sspingano il pilastro m in fori, cioè si sforzano caciarlo dal cientro di tale ottangolo’.
Even though the arithmetic result of 4,608,000 is correct, he instead writes in letters ‘se’ mjlion’ e secen’ 8 mila il peso del tiburio’ (‘six million and six hundreds 8 thousand the weight of the dome’): it may be an oversight, or it can be assumed that he has added the weight of the masonry panels between the stone ribs at a flat rate to the total. The arithmetic operations performed, which prove that Leonardo mastered two- and three-digit multiplication in column, are: 16 × 45 = 720; 720 × 800 = 576,000 (
Because if it were
The author has no competing interests to declare.
London, Victoria and Albert Museum
Leonardo da Vinci,
Leonardo da Vinci,
Madrid, Biblioteca Nacional de España
Leonardo da Vinci,
Milan, Archivio della Veneranda Fabbrica del Duomo di Milano (AVFDMi)
Milan, Archivio di Stato di Milano (ASMi)
Milan, Archivio Storico Civico di Milano, Biblioteca Trivulziana
Leonardo da Vinci, Codex
Milan, Biblioteca Ambrosiana, Leonardo da Vinci,
Paris, Institut de France
Leonardo da Vinci,
Leonardo da Vinci,