The original structure of the Duomo
Carlo Ferrari da Passano
The major restoration work carried out in 1967 on the ambulatory, choir and presbytery vaults, and on the large
dome within the crossing tower and the two bays adjacent to it, restored both the vaults and the impressive
crossing tower with its very fine dome to their original and natural magnificence, making them once again visible to
worshippers and tourists.
The architectural structures supporting the crossing tower, that is the four huge pointed arches, up to the impost of
the dome, were built in the second half of the 15th century by Guiniforte Solari who completed them around 1470.
The large and elaborately decorated brackets dating from the same period are carved with extraordinary creativity
and splendid craftsmanship; they support the fifteen statues decorating each side of the large Gothic arches.
The four pendentives, also dating from the mid-15th century, form the connection between the square of the
supporting piers and the octagonal shape of the dome; each pendentive is decorated by medallions with the busts
of the four Doctors of the Church: St. Ambrose, St. Augustine, St. Gregory the Great and St. Jerome.
Some of the sixty statues date from a period prior to the construction of the crossing tower, since they were
removed, as can be seen from certain details of their bases, from the niches of the capitals or from the large
intradoses of the stained-glass windows. They therefore provide an overview of sculpture in Lombardy in the 15th
century.
Some are more closely linked to the stylistic characteristics of Rhenish sculpture, others are more markedly local
in style and already more openly show the characteristics of the sculpture of the Duomo which was by then
approaching that of the 16th century.
The vaults restored by total removal of the old and crumbling plastering, which had been painted with tempera
several times during the 19th century to create the effect of ‘Gothic marble work’, were treated with strong plaster
to consolidate and protect them and this plaster was sponge painted in tone-on-tone colour to match the average
chromatic value of the previous decorations.
During this stage in the work, restoration was also carried out on the large rose-shaped shrine suspended above
the vault of the choir and containing the precious Holy Nail relic, the magnificent gilded-copper medallion made by
Beltramino da Rho between 1416 and 1425 and placed on the keystone of the semidome of the apse (replaced in
situ by a bronze copy) and on the monumental crucifix hanging from the top of the large Gothic arch at the
beginning of the presbytery, a splendid work of sculpture dating from the end of the 16th century.
It is reasonable and there are sufficient grounds to suppose that the work on construction of the Duomo began in
1386, the date inscribed on the stone placed in the first bay on the right of the Cathedral, and this can be accepted
even though it has not been possible to find any confirmation of it in the official documents held in the Archives.
Construction of the Cathedral of Milan was jointly decided by Duke Gian Galeazzo Visconti and his cousin
Archbishop Antonio da Saluzzo with the determined contribution of the population of Milan. Gian Galeazzo's strong
personality and ambition is well known, and they are demonstrated both by his versatile patronage of fine arts, to
such an extent that some of the most important architectural projects of that century are linked to his name, and by
the fact that in 1385, after imprisoning his uncle and cousins, he became the sole ruler of the state thus uniting the
Duchies of Pavia and Milan, as a probable first step towards conquest, not successful, of Italy or at least a large
part of it.
The Milanese Church and its Archbishop, after a millennium, aspired to build a new larger and more modern
Cathedral in place of the two basilicas used in that period: Santa Tecla and Santa Maria Maggiore. On the other
hand, the people of Milan longed for a period of peace and tranquillity after so many wars, conflicts and clashes
that had thwarted their hopes for greater affluence and for a spiritual and religious life consistent with Christian
teaching.
In view of such a series converging interests, and with a sense and decision that was clearly political, Gian
Galeazzo desired a Cathedral that the Church, the City and the People, who would be entrusted with the burden
and the commitment of the major building project, would take as a significant expression of his power. This is why
in 1387 he drew up the Articles (Statuti) of the Ven. Fabbrica del Duomo, upon which the institution that is still
operating is based, albeit in a form updated to suit the current situation. While this institution initially acted for the
Duke and now acts for the appropriate state institutions and for the diocesan ordinary, it is formed by laymen and
members of the clergy; within a very short time it became the only body responsible for the building and upkeep of
the Cathedral from both the architectural and economic-administrative point of view, as it has continued to be over
the ensuing centuries, and therefore the choral expression of the wishes and sacrifices of the people of Milan.
A psychological virus immediately crept into this model institution, fostered first and foremost by the majestic
building which had not been defined in the greatest detail and by the uncertainty of its design, so much so that the
Fabbrica's first engineer, Simone da Orsenigo, always behaved not so much in a leading role but as the site
manager for work conceived and developed by other Italian or foreign masters.
Doubts and uncertainties on the further development of the building became more frequent after a period of
feverish work between 1386 and 1391, during which the foundations, the piers of the apse and of the transept
were built in brick according to an outline design, followed almost immediately afterwards by the use Candoglia
marble, again under the supervision of Simone da Orsenigo, criticised because this sudden change of material
therefore brought a change in the design too. This was also due to the fact that from the very beginning there was
no figure to whom full trust and responsibility could be assigned, allowing him to courageously and determinedly
prepare the working drawings and models, the static calculations and the decorative details appreciated by the two
main patrons who had perhaps based the grandiose project only on purely planimetric and approximate
indications. This brought about a rising tide of criticism and doubts on the building and therefore the arrival of
Nicolas de Bonaventuris to whom the design and creation of the three windows of the apse was entrusted,
followed by his rapid dismissal and the summoning of Matteo da Campione, then working on the construction of
the Duomo in Monza, who diplomatically declined the appointment as engineer of the Duomo of Milan, the position
previously held by Simone da Orsenigo, limiting himself to suggesting that the section of the piers of the crossing
tower and the related foundation should be increased by three quarters of a cubit. The constant succession of
opinions given by renowned artists for such a patient suffering only from precocious and uncontrolled growth
confirms the initial diagnosis and provides the broadest justification for it.
In 1391, it is worth mentioning that the opinions of Bernardo da Venezia and Gabriele Stornaloco from Piacenza
were requested by the Representatives of the Fabbrica through the Duke causa discutendi cum inzigneriis dictae
fabricae de dubiis altitudinis et aliorm de quibus dubium erat inter dictos inzignierios.
The learned mathematician from Piacenza gave a necessarily a posteriori geometrical justification for the structure
of the Duomo in that the piers had already been built, almost as if to give the cathedral which had up to that point
been conceived and constructed according to improvisation and intuition a licence of architectural and
mathematical exactitude as well as of stylistic coherence in contrast to the rigid northern European rules. One of
the most critical moments in this phase was certainly the arrival in Milan in December of 1391 of Heinrich of
Gmünd, who harshly criticised Stornaloco's work and designs. Due to the troubling doubts raised by an architect of
great renown and moreover a foreigner, the Representatives of the Fabbrica, with no clear final design and above
all without a strong figure who could take upon himself all the responsibilities inherent to a construction conceived
as a whole only by site engineers or artists responsible for the sculptural decorations, ordered Heinrich of Gmünd
to make a written report of his criticisms. This document was discussed on 1st May 1393 and gives interesting
information on the heights and size of the structures already built, on the one hand criticised and almost in need of
demolition, while considered by the Italian engineers to be safe and with no need for alteration. It also highlights
the original flaw of not preparing a full design defined in all its details, in that at that time the load bearing
structures of buildings and their decorations had to advance at the same time and so, urged on by a converging
enthusiasm for their work, the construction of the Duomo, at least at this initial stage, always preceded and
conditioned the formal design and the final solutions.
During the conference of 1392, all the doubts put forward by Heinrich of Gmünd were rejected by the Italian
engineers and he was naturally dismissed; a design and a plan of work was set down for the years to come, in
order to speed up the completion of the apse and the transept which took place from 1392 to 1400 under the
supervision of Giovannino de Grassi (who died in 1398) and Giacomo da Campione (who died in 1399). After
achieving these results, the umpteenth crisis occurred, fuelled by more doubts and new uncertainties and
misgivings both of an artistic and static nature. On 13 April 1399 therefore, another foreigner arrived, again
summoned by the Duke, and this was Jean Mignot who, with the authority deriving from his international renown,
made wide-ranging structural and stylistic criticisms of the building which had already been defined in its essential
elements including the four piers of the crossing tower constructed up to its impost. It was unavoidable that this
time too serious differences of opinion should arise between the French group led by Mignot and the Italian
engineers. The dispute reported by Mignot directly to the Duke became official and therefore the Representatives
were forced to take a stance ordering him to make a written report of his objections. This document transcribed by
a notary listed all the finding and serious defects found by Mignot with severe statements regarding flaws in the
static stability and errors in the construction of the cathedral, in particular with regard to the piers. Mignot's
findings, due to their seriousness as well as his insistence, baffled the Representatives and the Duke to whom
Mignot had appealed directly and so they asked the opinion of three other French engineers, Simoneto Nigro,
Giovanni Sermonerio, Mermeto di Savoia who on 21 February 1400 gave an opinion in favour of Mignot,
explaining their point of view directly to the Duke in Pavia on 22 February 1400; given the serious divergence of
opinions the Duke decided to consult Bernardo da Venezia and Bartolomeo da Novara too on 8 May 1400, in
order to counterbalance in a certain sense the opinion of the French group. However the judgement expressed by
the Italian consultants was a classic example of opportunism and dependency. Indeed, having learnt of the order
of the Duke to erect a sepulchral monument to his father Galeazzo in the ambulatory, they revived the idea of
building a Chapel in the Duomo, perhaps going back to a structural conception devised by Simone da Orsenigo in
May 1392 which consisted in the construction of transversal walls in order to provide greater static resistence to
the building. This idea was never used, but it did however result in temporarily reconciling the two opposing sides
in an opportunistic compromise and naturally caused a considerable delay in the work. The dispute in fact
continued with actual court proceedings instituted on 15 May 1401 between the French Master builders led by
Mignot and the Italian engineers with subsequent contributions by the Duke and the Archbishop while the
Representatives took sides with the Italian engineers partly so as not to agree to the drastic and unpopular
proposals of the Frenchmen to demolish part of what had already been built. In the end, the Fabbrica took
advantage of an error by Mignot in constructing a capital and other minor works to dismiss him for good on 22
October 1401.
Six centuries later, when impartially and objectively considering the opinions of Heinrich of Gmünd, who was a
reliable expert on an architectural style that was new for the Italian engineers who on the contrary were particularly
expert in Romanesque architecture, such drastic and worrying opinions may seem dictated by a hostility based on
a design and executive situation that was totally premature. Indeed, the feeble hints at a protective structure made
up of small turrets (pinnacles) and the already defined and constructed height of the piers shown in Heinrich of
Gmünd's report seem very little as compared to the static demands of our Duomo. For them, a consolidated and
well-tried method for avoiding distressing and dramatic collapses was the absolute need, when building the
structures of the piers and the Gothic arches, to provide for and construct inverted arches and buttresses to
counter the horizontal thrusts transmitted by them. The solutions adopted for such structures built on the other side
of the Alps for Notre Dame in Paris, St. Peter's in Cologne and St. Stephen's in Vienna were different, original and
jealously guarded by strict secrecy both by the designers and by the patrons of these cathedrals. On the contrary,
what had already been built or was planned by the Italian engineers who were proud of their building experience
had perhaps already intuited an original solution formed by two vaults, the interior ones and the upper ones
supporting the pedestrian roof terraces of the Duomo created by a double system of vaults rotated 90 degrees
against each other to effectively counter the thrusts of the Gothic arches on which both would later weigh. This
device used for the structure of the vaults makes their loads weigh vertically on the Gothic arches beneath them
inside the Cathedral, thus neutralising the horizontal thrusts without the need for external buttresses, as reality and
time have shown.
It was not therefore merely a case of a clash between two different architectural cultures and experiences, nor
least of all petty envy for a commission assigned to them, but expression of an authoritative sense of responsibility
and building experience of the consultants who were exponents of an architectural style that had already been
created in their own countries with constructions for which solutions of structures suited to ensuring their static
stability had been adopted from the very beginning.
In conclusion, our Duomo therefore with its 132 pinnacles and the rampant arches built only in the 19th century
has relied in the past centuries and will continue to rely in the centuries to come on this original solution,
aesthetically enhancing its appearance of soaring upwards with its elaborate external decoration, concluded with
the main spire built in 1774 topped by the statue of the Our Lady of the Assumption. We do not know and perhaps
never will know who devised this admirable static solution, but the winning attitude of the Italian architects and
engineers against their foreign colleagues, who predicted the certain collapse of the cathedral, seems likely to find
a probable answer by browsing through the documentation and stormy events of those years. It seems to me,
however, that this historical digression may suggest the explanation that the Italian engineers were the keepers of
this ingenious and secret solution gained from their professional experience and then applied to our Duomo. It
proved to be successful for the structures of our Duomo against the severe defamatory judgements of Heinrich of
Gmünd and Jean Mignot, sad prophets of certain ruin. The same design prepared by Stornaloco, the outstanding
mathematician from Piacenza, precisely defines the dimensions of the building that was then constructed and
therefore it may perhaps lend feasibility to this hypothesis, which is somewhat daring, but on the other hand
ascertained, for this original and unique structural solution used on our Duomo.
Lastly I am obliged to judge the conduct of the foreign engineers summoned to give their opinion and their severe
judgement with impartial objectivity. It was not therefore merely a case of a clash between two different
architectural cultures and experiences, nor least of all petty envy for a commission not assigned to them, but one
of exponents of a different architectural style but certainly no less valid than ours already widely applied in their
own countries with constructions for which solutions had already been experimented with structures suited to
ensuring their static stability and which are still studied and admire to this day.
At this point all that remains is to mention the tourist use of the Duomo's terraces which, especially on Sundays,
attract the citizens of Milan and tourists, tempting them with the possibility of enjoying a fascinating and tasty
pause accompanied by drinks, salami and a good light wine, as they used to in the 19th and early 20th centuries,
and the longest-living of them will certainly still remember this marvellous experience.
Now we pause to admire the superb panorama that for over six centuries dominates the city and beyond, as
careful and responsible guardians we are proud and grateful to our forefathers who built this great work of art and
architecture offering a magnificent example of religious and secular ideals over time and in the world as the
symbol of Milan