Renaissance Saint Peter's: Michelangelo

Michelangelo’s career began and ended around Saint Peter’s Basilica.
His first great success as an artist was the famous marble Pieta intended for the tomb of a French cardinal in St. Peter’s, carved while Michelangelo was still in his 20s.


Michelangelo's Pieta photographed in 1964 when it visited the New York World's Fair. It was displayed, and photographed, at the angle it was originally to be seen. It was originally much lower and closer to the floor than it is now, on a high plinth behind bullet-proof glass.

Michelangelo takes a subject largely invented in Northern Europe, and full of tragic irony and pain – the Virgin Mary holds the body of her dead Son in her lap as she once held him as a child – and invests it with an unearthly sense of repose. The sharp tragic forms of Northern Gothic art are remade with a classical sense of grace and grandeur in a work that is completely original. The Pieta is beyond all the categories of art.
At the end of his life, Michelangelo would take charge of Saint Peter’s, making it too into something beyond all the categories, something completely original.


Bartolomeo Ammanati, Saint Peter's as it appeared about 1569

In 1546, the latest heir to Bramante’s great project for the new Saint Peter’s, the Florentine architect Antonio Sangallo, died. Since Bramante’s death in 1514, work proceeded very slowly on St. Peter’s. Much of the nave of Constantine’s ancient church still stood, and would remain standing until the 17th century. Many architects had come and gone since Bramante’s death, including Raphael and Antonio’s father Giuliano. The crossing arches completed by Bramante stood with construction largely finished on a couple of the great arms to support the dome. Much of the interior articulation was already finished according to Bramante’s design. Antonio’s family and partners fully expected to inherit the project, and its income.

Pope Paul III created a commission upon Sangallo’s death to see if work on the project could be accelerated. One of the experts asked to serve on this commission was the aging Michelangelo, now in his 70’s. When asked his opinion, Michelangelo said that Sangallo’s design should be scrapped and that his heirs should be fired and sent back to Florence. He accused them of corruption, and faulted Antonio for departing so far from Bramante’s original design.


Antonio Sangallo's proposal for St. Peter's, plan and model

Sangallo planned for a huge church. Michelangelo pointed out that much of the Vatican Palace, and perhaps even the Sistine Chapel, would have to be pulled down to accommodate the new church. Sangallo added extra ambulatories, aisles, and a nave to Bramante’s design. Michelangelo pointed out how dark the interior would be, and indeed, when we look at Sangallo’s plans, they are full of elaborate and awkward schemes for lighting the dark interior. Michelangelo complained that the church would be so vast and complex that it would become a nest of crime; he said that not even a company of soldiers could clear the whole building at sunset before closing.

Sangallo's original wooden model of his proposed design



Sixteenth century engraving of Sangallo's proposed design for the interior. Note all the elaborate and strange angles of the windows (including an odd sky-light) in the cut-away walls on the far right.

Sangallo’s original wooden model for his proposed church survives by great good luck. When we look at it, we can see what Michelangelo really objected to. The design is a huge lummocking monster, made up of quotations from ancient Roman monuments such as the Colosseum, the Pantheon, and the Theater of Marcellus. Sangallo’s design has no focus, nothing to tie all those parts together.

Michelangelo hated Bramante bitterly, even long after the architect’s death. He accused Bramante, probably unjustly, of conspiring to put him on the Sistine Chapel job so that Bramante could persuade Pope Julius II to rebuild Saint Peter’s. It is more likely that the initiative to rebuild the church was entirely the Pope’s. Michelangelo opposed the destruction of the ancient church. However, Michelangelo admired Bramante’s design for the new St. Peter’s very much, and he faulted Antonio Sangallo for departing too far from Bramante’s original conception.

Michelangelo proposed to the Pope that he could make a better and more efficient design that could be built much more quickly, incorporating what was already built. Michelangelo sealed the deal when he said that he would do this work for free, that he would take no salary (Michelangelo, it should be pointed out, was a very wealthy man at this phase in his life).

In 1547, Pope Paul III appointed Michelangelo head of the Fabrica, the construction company, of Saint Peter’s Basilica. Michelangelo was 72 years old at the time of the appointment. Immediately, he faced resistance from the Fabrica and intrigues from the Sangallo family and their partisans. Dr. William Wallace, a noted Michelangelo scholar, suggests that based on the surviving evidence, Michelangelo was not above resorting to force and intimidation to get his way. Michelangelo’s quarrymen (many who had worked for him all their lives, and so had their fathers) would sometimes waylay members of the Sangallo circle, beating the stuffing out of them and threatening them with worse if they didn’t leave Rome. Even after he had taken control of the whole project, Michelangelo still faced hostility and constant intrigues against him, trying to take advantage of his failing health. However, even while suffering constantly from kidney stones, and frequently bed-ridden, the elderly artist took firm control of the project and imposed his will. When he took over, work on the immense project proceeded quickly and much was finished before Michelangelo’s death in 1564.




It is Michelangelo more than anyone else, except maybe Bramante, who is responsible for the St. Peter’s that we see today. After his death, his commanding ghost looked over the shoulders of all the later architects who worked on the building.

Michelangelo's proposed plan for Saint Peter's Basilica

Michelangelo’s first act upon becoming the new architect was to take a great eraser to Sangallo’s design, getting rid of all the ambulatories, aisles, and bell towers, and returning to Bramante’s original vision of a centralized church. Michelangelo dramatically simplified and concentrated Bramante’s original plan. Michelangelo working without a salary gave him a free hand. He was able to tear down those parts of Sangallo’s church that had already been built and impeded Michelangelo’s own design. Still, Michelangelo did little to alter what was already built. Most of what we see in the larger forms of the interior of Saint Peter’s is Bramante’s work. Michelangelo did little to change what had already been built on the interior.


Saint Peter's from the southwest.


Most of Michelangelo’s work on Saint Peter’s is on the exterior and is very original and extraordinary. Michelangelo’s articulation of the exterior is focused and concentrated in a way that Sangallo’s is not. Michelangelo sculpts his building masses while Sangallo piles his up out of smaller pieces. Michelangelo borrows some of what Bramante did with the interior articulation, and takes it in a whole new direction. Like Bramante, he divides the exterior into a series of units divided by massive double pilasters, the whole thing tied together by an enormous entablature. Unlike Bramante, those units are not all uniform in size. Not only are the massive pilasters doubled, but they sit against 2 and 3 levels of backing. The vertical reach of the pilasters is not checked by the entablature. On the contrary, it breaks the entablature and continues on up through the attic storey without interruption.
James Ackerman in his great book on Michelangelo’s architecture points out that Michelangelo’s great gifts to the design of Saint Peter’s are unity and economy. He also points out that Michelangelo never felt bound by the decorum of classical architecture as the Renaissance understood it. He feels no compunction about breaking up a huge and important entablature with the vertical reach of the pilasters. He transforms Sangallo’s secondary support piers into spiral stairwells, and brilliantly adds extra windows between pilasters to light them. They are at an angle to the corners of the massive square of Bramante’s original plan, and the hemicycle apses. Renaissance classical decorum would have required that all those angles be a uniform 45 degrees. Ackerman demonstrates that Michelangelo simply thought of the shortest distance between 2 points in a straight line. Michelangelo thinks less in terms of geometric harmony than in terms of connective tissue. Michelangelo brings out the organic quality always latent in classical architecture since the days of the ancient Greek temple. The pilasters become ribs and bones. Entablatures and cornices become connecting tendons. The whole exterior mass seems to heave and subside like a great muscular male torso.



The very unclassical vertical reach of the pilasters of the exterior finds its climax in the great dome of the church. At 452 feet high, it remains unchallenged as the tallest dome in the world. It is also among the most celebrated and imitated of all domes ever built. As stirring as it is, its design was hardly inevitable.




Michelangelo struggled over the dome more than with any other part of Saint Peter’s. There remains a lot of argument among historians over whether indeed that inner struggle was ever settled, and if so, are we really looking at Michelangelo’s solution. Michelangelo lived long enough to see all the exterior articulation on Saint Peter’s finished, and to see the dome rise as far as the drum. After his death, the dome was completed by the sculptor Giacomo della Porta.

Michelangelo first looked for inspiration to a dome he had known and loved since his boyhood, the great brick dome of the Cathedral of Florence designed by Filippo Brunelleschi more than a century before. Brunelleschi’s dome is an inspired hybrid of Roman building forms and Gothic design and construction. Michelangelo apparently had something like that in mind at first. He wrote to friends in Florence to send back measurements of the dome and its lantern.
The influence of Brunelleschi’s great dome shows clearly in Michelangelo’s early drawings for Saint Peter’s dome. Like the cathedral in Florence, he wanted a ribbed double shell dome topped by a lantern.


Michelangelo's sketches for Saint Peter's dome showing a double shell dome and a lantern.



Michelangelo's sketch of the dome showing the double shell with an early idea for the articulation of the drum. This design combines Bramante's doubled columns with the occulus windows of the Florence Cathedral



Cigoli's drawing of Brunelleschi's double shell design of the dome of the Florence Cathedral


Florence Cathedral


The argument among the historians is over how much or little Michelangelo wanted the dome pointed like the dome in Florence, and over the size of Michelangelo’s proposed lantern compared to what della Porta built.


Etienne Duperac's engraving of Michelangelo's final proposed design for Saint Peter's. Michelangelo intended 4 smaller domes which had not yet been designed before his death. There are now only 2 of those small domes, designed entirely by Giacomo della Porta.

According to surviving evidence, Michelangelo intended a much more spherical dome than the Gothic dome in Florence, and with a larger lantern than what was built. Ackerman faults della Porta for departing from Michelangelo’s intentions. Howard Hibbard suggests, plausibly, that della Porta returned to the Florentine pointed dome for engineering reasons; a heavy stone lantern is much more securely supported on a pointed dome than on a spherical dome. Others like Sir Kenneth Clark credit della Porta for returning the design to its original sources of inspiration in Gothic art and in Brunelleschi’s dome. I’m inclined to agree with Kenneth Clark. Della Porta, usually a mediocre sculptor, rose above his own limitations and made inspiration out of an engineering necessity. The more pointed dome, in my opinion, fulfills the aspirational reach of the rest of the building with a much more satisfying climax than Michelangelo’s original hemispherical dome with a big lantern.





Probably no other dome built before or since has so much thematic content concentrated in so clear and concise a form. The whole history of the Church is summarized in that dome. The dome is a Roman building form. Christianity appeared during the Roman Empire. It is a round structure built over Peter’s traditional tomb, like the round churches of Constantinian Christianity with their ambulatories to accommodate the rite of circumambulation. It is a dome resting on four enormous arches recalling its great Byzantine predecessor Hagia Sophia. The vertical aspirational reach of its point and its ribs and buttresses deliberately calls to mind medieval Gothic architecture.











The dome calls to mind the vault of heaven; not the heaven of the stars and planets with their gods of the cosmic order imagined by the Romans, but the glorious heaven of Christ and the company of the saints. What we see in St. Peter’s dome is not the established order of earthly power projected into the heavens, but the exhilaration of the hoped for Heaven at the end of all history and all longing.

Bust of Michelangelo on the dome of St. Peter's.