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Weary and tired of working? Imagine you are 71 years old and have spent over fifty years working for difficult people in a physically and mentally demanding job, managing complicated projects. Then your boss asks, in reality tells you, “I want you to build the new St. Peter’s Basilica in Rome.”
You think, no, I can’t, I’m too tired, I’ll never live to see it completed, I have other work to do. That’s how Michelangelo reacted, then reluctantly accepted the responsibilities as supreme architect of St. Peter’s in 1546 at Pope Paul III’s request. The last 17 years of Michelangelo’s life were devoted to St. Peter’s. He didn’t do it for the money or prestige. It was his divine salvation. His design and construction of the monumental dome stands out as one of his often-overlooked masterpieces that has influenced other buildings for centuries to come.
Michelangelo in Florence and Rome
Michelangelo di Lodovico Buonarroti (1475-1564) is a mythic figure, the creator of the Sistine Chapel frescoes and sculptures such as the David and the Pietà. He is often portrayed as a loner, unable to work with others, obstinate, friendless. Nothing could be further from the truth – except the stubbornness. We begin to get a clearer understanding of Michelangelo the person through his correspondence, poetry, peer accounts, and biographies, although the later were mostly for public relations constructed by Michelangelo and his close circle. We know a great deal about him from banking records, over 500 letters, and contracts.
We know he lived modestly, rejected a lavish lifestyle, and had one principal goal: create a financial legacy for the Florentine Buonarroti family. He had a good sense of humor, was a great dinner companion with his friends, a pious Catholic, loved good wine, pears, and cheese, especially from Florence. Openly and frequently critical of poor workmanship and bad wine (he complained to his nephew in Florence that the wine he sent him wasn’t as good as last year), when it came to stone carving, he never settled for second best. And he died filthy rich.
Born to a minor aristocratic family, a fact he played up his whole life, Michelangelo was apprenticed at age 14 to a prominent Florentine painter, Domenico Ghirlandaio (1448-1494). He learned in an organized, systematized workshop how to prepare plaster for fresco, grind pigments, drawing, wet and dry fresco technical preparation; skills he would put to good use for decades to come. Lorenzo de’ Medici hosted the young talented Michelangelo in his Florentine house for about four years where he had access to the elite thinkers and philosophers of the day, including making connections with future patrons. Michelangelo’s stay at the powerful banking family’s residence served him well as some future Medici were cardinals and even popes. Two early sculptures defined his mastery of the heroic figure: the Pietà (1498), now in St. Peter’s Basilica, and the David (1501-4) in the Galleria dell’Accademia in Florence.
(L) Michelangelo, Pietà, St. Peter’s Basilica, Rome, 1498/99-1500. At age 23 he took only a little over a year to carve the Pietà for a French cardinal’s grave. It is the only work of art he signed, inscribing his name in the strap between the Virgin’s breasts.
(R) Michelangelo, David, Galleria dell’Accademia, Florence, public domain, Pixabay, 1501-4. He carved this monumental statue in three years.
Almost twenty years after his apprenticeship to Ghirlandaio, Michelangelo was called to Rome by Pope Julius II to paint the Sistine Ceiling (1508-12). He really hadn’t worked much in fresco for years, and considered himself a sculptor, but he acquiesced, much as he would some thirty-eight years later to build St. Peter’s. Michelangelo could not have imagined he would return again to Rome and be given another enormous task, this time by Paul III, to paint the Last Judgement on the wall of the Sistine Chapel in 1536. Just a few years prior, in 1531, the Florentine Republic fell and effectively ended Michelangelo’s artistic life in Florence. Although the de’ Medici still ruled, the city no longer was a republic ruled by a council, now a monarchy controlled by heredity.
Michelangelo was a staunch supporter of the republic. He became an exile in Rome, along with many Florentines. He longed to return to his beloved hometown, but never did. In essence, he grudgingly became a papal artist and architect in Rome until his death. He acted as distance architect for a few projects in Florence, most significantly the façade of San Lorenzo, where he supervised three hundred workers and their supply chain. The de’ Medici commissioned Michelangelo to build a library for their collection. This work started while he lived in Florence (1524) but ended with him managing it from Rome. He never saw it completed. Known as the Laurentian Library, Michelangelo imaginatively used some elements such as paired columns, supersized architectural elements, and pediments above the window-like tabernacles that he would re-use in St. Peter’s. His library staircase looks sculptural and modern. The staircase was built in 1559 from designs he submitted from Rome.
Building New St. Peter’s
The original St. Peter’s Basilica, built upon the spot where St. Peter was crucified, was a crumbling ruin. Constantine, the first Christian Roman Emperor, was the patron of the Old St. Peter’s in the early 300s CE. New St. Peter’s was commissioned by Julius II in 1505 and he assigned Donato Bramante (1444-1514) as architect. His design was so lavish the church needed to sell indulgences to help raise funds for it. Bramante was a good designer and a mediocre engineer. His design called for a centralized church with a monumental dome over the center of the crossing. When he died at age 70, the four arches of the crossing and four pendentives, foundations of the three arms of the cross, and some chapels were complete.
Each subsequent architect changed the plans, some radically. Some didn’t move construction along, were poor project managers, or just stalled because they had other responsibilities, or couldn’t address the engineering issues. Antonio da Sangallo (1484-1546) came from a family of respected builders. Antonio was trained specifically as an architect, not a painter, and had extensive experience. He worked on the building site of St. Peter’s for some time before being appointed as papal architect, for which he served as for ten years. His model for St. Peter’s didn’t resemble Bramante’s much at all and was a huge, sprawling building. If built, it was possible the Sistine Chapel and Pauline Chapel, both containing Michelangelo’s frescoes, would have to be torn down.
Sangallo built an elaborate, costly wooden model. It is unrecognizable as the St. Peter’s we know today. Michelangelo intensely disliked his ideas. Besides being public enemies, as a result from other competing projects, Michelangelo alleged that Sangallo’s design would promote crime with all its niches and side chapels – he said there were enough dark areas to ensure nuns would be impregnated. Sangallo disrespected Michelangelo for lack of building experience. Once again, when Sangallo died suddenly, all work ceased on St. Peter’s. This time Paul III tapped Michelangelo to take over.
Michelangelo the Boss
Michelangelo’s first turned his attention to the deficits of Bramante’s engineering and convincing the papal hierarchy and Sangallo’s crew that Michelangelo knew what he was doing and to abandon Sangallo’s plan. The piers Bramante built to support the dome greatly underestimated the thrust and weight they would have to bear. Cracks had appeared in the crossing vault. The building site was a disaster. Poor workmanship abounded along with graft, bribery, and low-grade building materials purchased at high prices. The grounds were strewn with crumbling pieces of marble from old St. Peter’s and rubble from decades of five architects who preceded Michelangelo. And the site was open to the sky. Workers loyal to Sangallo resisted Michelangelo’s initiatives at every step.
Michelangelo reverted to a Bramante-type Greek cross design. He had to undo twenty years of Sangallo’s work, enlarge the four piers, ensure procurement of top-notch goods, and institute good onsite work practices. And as a sculptor he knew stone unlike other previously appointed architects. He also knew the street smarts of building sites: how to obtain good rope, essential for hoisting and holding materials, how to build appropriate scaffolding, block and tackle, pulleys, re-cycling building materials from Old St. Peter’s instead of discarding them. He designed enclosed helical ramps on the piers so donkeys and mules could tromp building supplies and water up high to workers. He oversaw travertine purchasing and delivery from quarries nineteen miles away and no one got away with shoddy materials arriving on site.
Workers were on site six days a week and until Michelangelo was in his eighties, he arrived before they did. Payday was Saturday. Bells sounded to mark the hours and midday meals. Michelangelo was a hard worker himself and eventually earned their respect. The work went slowly. To make a column capital, Michelangelo would make drawings and an assistant would enlarge the drawings and produce a pattern, then cut it from tin. The skilled carvers would use the tin sheets as a guide to carve the marble. It could take eight months for an experienced skilled carver to make two column capitals. Michelangelo knew he would never live to see the building even close to completion. He endeavored to complete as much as he could despite being involved in many other projects, bad weather, changes in popes, and political unrest.
Michelangelo knew that if the drum (the base of the dome) could be completed or nearly completed before he died that the next supreme architect would be obliged to continue with his plan. By the time of his death his artistic reputation was revered. To this day only two artists are acknowledged as primarily responsible for St. Peter’s: Michelangelo and Gian Lorenzo Bernini.
The Architecture of the Dome
The sheer number of decisions and technical aspects confronting Michelangelo in constructing the tallest dome in the world (448 feet from ground to exterior cross) is daunting. How much travertine should be quarried for the dome? To what degree should the quarry workers rough out the stone before transport? Should the columns be hoisted or rolled? Where to stable the donkeys and mules? Who would and how often would animal manure need to be cleared and disposed of?
To complicate matters, measurements were not standardized at the time, as a braccio (an arm’s length) measured differently in each major city: .670 m in Rome but .584 m in Florence. Michelangelo, ever the micro manager, made sure the same braccio was used from the quarries to the workers on site. He needed to make daily decisions small and large as well as keep a vision of the big design and engineering picture.
However, Michelangelo was not perfect. An expensive and labor intense error was made in miscommunication between him, foremen, and workers regarding the transept barrel vaults co-joining with the vault of the apses. At age 82, it was now not feasible for him to make the journey daily to the building site. He took responsibility and had the vault dismantled, setting back work by months. He agonized over his mistake and wrestled with how to solve the problem. Most likely the concept of losing respect was also a factor since it had taken a while for him to earn it from the workers.
In spite of all the weekly and monthly decisions, changes in the workforce, multiple projects, and naysayers, Michelangelo knew what he wanted the dome to look like. He had about a dozen concepts sketched out and reluctantly built a model, but he knew no amount of drawings or wood models could anticipate stress from stone and engineering problems that arose during the building process. He thought structure and stability first, aesthetics second.
Filippo Brunelleschi’s dome over Florence’s Santa Maria del Fiore and the Roman Pantheon proved to inspire Michelangelo in style and form. The cathedral dome in Michelangelo’s home town would have been familiar and renown for its architectural problem solving and ingenuity. The dome was finally built in 1420-36, however, the problem of Florence’s dome had eluded architects for nearly a century, leaving the church open to the sky. No one could solve how to build a dome so large yet structurally sound. Brunelleschi solved the problem by building a brick dome 171 feet above the floor with a 144-foot span using a double shell supported by hidden stone and iron chains.
The Pantheon (123-25 CE), widely admired by Michelangelo and other artists, is built of concrete. Its hemispherical shape and brilliant Roman engineering had amazed people for centuries. Michelangelo used a variety of prototypes, seeking to mix and match elements that when placed together are original, such as in his Laurentian Library. He modified the pediment (triangular shape above the columns) and uses them in the dome and Laurentian Library in new and inventive ways. Structurally, St. Peter’s dome is as wide as the Pantheon but much higher. And it was to be built out of travertine marble. It had never been done before.
Pantheon, Rome, exterior and interior of the dome,123-25 CE.
Michelangelo concentrated on support for the dome via the drum and buttresses. If the drum was complete, and it was before he died, then others could finish the dome as he intended. More or less, that is what happened. Subsequent architects did not significantly alter his concept. Although others may have completed the dome, it is definitely Michelangelo’s design. The drum is the dome’s foundation and the buttresses provide support. His design masks the massive supporting elements with architectural repetition of design. The dome rises effortlessly and gracefully. Here’s how he accomplished that.
The drum stands fifty feet tall. Michelangelo’s use of paired columns on the exterior, and paired pilasters on the interior, provide aesthetic unity. Columns and pilasters provide a visual rhythm, vertical emphasis, and continuity. His use of paired columns for structure and visual appeal are unique. Michelangelo varied the size of the architectural elements as well as the shape. The paired columns on the drum are three-quarters round, not free standing. Similar techniques are used for the interior with giant paired pilasters instead of columns. The lantern has mini columns: 32 columns in 16 pairs, the same quantity as on the drum.
The sixteen dome ribs rise from the attic (the horizontal band with small impost blocks and columns interspersed with garland) and curve upwards towards the lantern. The lantern is the final element topped with an orb and cross. The weight of the lantern holds the ribs in place as well as adding light to the interior. Sixteen ribs adorn the lantern.
Windows diminish in size from the drum to the lantern. Drum windows are topped with alternating circular or triangular shaped pediments on the exterior and interior. The windows on the dome are miniature versions of the drum windows. This repetition of elements and repeating the number of architectural elements gives the dome its visual appeal as well as providing massive support.
The Four Popes of the Dome
Paul III (1468-1549) had a close relationship with Michelangelo. When he died, Michelangelo genuinely grieved the loss of his friend. They came from similar Florentine backgrounds and fraternized in Lorenzo de’ Medici’s circle. Michelangelo shared his Florentine wine and pears with Paul, as pears were considered the upper-class fruit at the time. Michelangelo lived in the area by the Colosseum, not at all a fancy neighborhood, more known for its meat market. It was about a forty-minute walk from his home to the Vatican. Paul once graced Michelangelo with a visit to his humble home, which was quite an honor.
Paul also gave Michelangelo a lot of work to do. The first commission was the Last Judgement on the wall of the Sistine Chapel (1536-41); redesign of the Campidoglio (Capitoline Hill) begun about 1538; frescoes in the Pauline Chapel in the Vatican (c. 1542-50) which were Michelangelo’s last frescoes; taking over from Sangallo the design and building of the Farnese Palace (begun 1546); and finally St. Peter’s (begun 1546).
Each pope came from a different political family which made navigating their artistic wants and desires fraught with tension. Paul was refined and from the Farnese family; his successor, Julius III (1487-1555), was far more uncultured, and from the del Monte family. Julius was considered rather boorish compared to his predecessor. Although they were never friends, Julius respected Michelangelo greatly and proceeded to add to his workload. He asked Michelangelo to redesign Bramante’s Belvedere staircase in the Vatican, a fountain, and act as an advisor on a new building in the then suburbs, the Villa Giulia, to be used for his family. Now an Etruscan museum, papal funds were used for this extravagance including a frescoed curving loggia, large palace, nymphaeum, courtyards, and a mere 36,000 plantings. In addition, Michelangelo consulted on other civic and religious projects. At the time Michelangelo was in his mid-seventies.
Paul IV (1476-1559) ruled for only four years, much to everyone’s relief. He was a staunch believer in the Reformation, and did not accept any notions of being saved by faith. Michelangelo had to suppress his own ideas about faith and grace in order to survive. Paul was rigid and inflexible. Tensions between the Vatican and Spain heightened to the point where war was a real threat and Michelangelo fled Rome for over a month to Umbria. The situation in Rome was dire with little food, unrest, lawlessness, and work at St. Peter’s and the other sites came to a halt. Work resumed only in 1557 when Michelangelo was 82.
When Paul died, riots ensued, normal during interim pope-less periods, until a de’ Medici pope was elected, Pius IV (1499-1565). Pius added to his workload: make over the Roman Baths of Diocletian into the church of Santa Maria degli Angeli, and also remodel the Portia Pia city gate. In addition, Michelangelo worked on the Sforza family chapel and the de’ Medici family asked him to design a new church specifically for Florentines in Rome, San Giovanni dei Fiorentini. The last five years of Michelangelo’s life was spent primarily on St. Peter’s, but only as a consultant designer on other projects. It became harder for him to make the trip to St. Peter’s and he relied on his trusted inner circle of foremen, supervisors, and skilled carvers to carry out the work based on his designs and concepts.
After Michelangelo
Michelangelo died February 18, 1564, just weeks shy of his eighty-ninth birthday. Having far outlived normal life expectancy he remained mentally sound, although physically frail. He came down with a fever and died five days later, surrounded by close friends, but regretfully not his nephew Lionardo from Florence, who arrived too late. An inventory of his house was taken as he died without a will. He lived simply, but locked in a chest was sixty-six pounds of gold, a large fortune at that time. His frugality and talent allowed him to accumulate significant real estate in Tuscany and cash. Sadly, most of his close friends and all of his brothers proceeded him in death. His nephew Lionardo and wife Cassandra, had only one surviving son, Buonarroto Buonarroti, having had four other children died in infancy. Michelangelo's accumulated wealth essentially went to one nephew and his son.
Michelangelo completed only about twelve percent of St. Peter’s during his tenure, yet the Basilica owes its basic architectural design to him. Giacomo della Porta (c.1533-1602) and Domenico Fontana (1543-1607) completed the dome in 1590. Pope Paul V appointed Carlo Maderno (1556-1629) architect in 1602. After much debate, and need to enlarge the nave of the church to accommodate more people, Michelangelo’s plan was modified from a centralized Greek cross plan to a Latin cross, resulting in extending the nave.
The unfortunate consequence is that the dome is partially obscured from the piazza. The best viewing of the dome is from the Vatican museums, gardens, and farther down the Via della Conciliazione as one approaches St. Peter’s. Maderno’s façade has been criticized for its proportions (too wide for its height) and not fitting with the whole of the architectural design. There was a rush to finish the church and in 1615 it was ready for services. It wasn’t until the 1670s that Gian Lorenzo Bernini and his crew finished interior decoration, the Baldacchino, statues, Cathedra Petri, and piazza.
St. Peter’s Basilica was nearly 170 years in the making from concept to completion. If you are wondering how Michelangelo’s design impacted future civic and religious architecture, look no further than St. Paul’s Cathedral in London (begun 1675), the United States Capitol in Washington D.C. (built 1850s), or other U. S. state capitols and churches.
The Main Architects of St. Peter’s
Donato Bramante
Giuliano da Sangallo
Raphael Sanzio
Baldassare Peruzzi
Antonio da Sangallo
Michelangelo
Giacomo Vignola
Giacomo della Porta
Carlo Maderno
Gian Lorenzo Bernini
Popes during Michelangelo’s Tenure as Supreme Architect of St. Peter’s Basilica
Paul III
Julius III
Marcellus II (ruled only 22 days)
Paul IV
Pius IV
Architectural Terms
Attic: A small extra story just between the drum and the ribbed dome with impost blocks.
Buttress: Supports an arch, vault, or dome. French Gothic churches used flying buttresses; Italians preferred more subtle buttresses.
Capital: Refers to the decorated top of a column or pilaster which provide support for the horizontal member above the column or pilaster.
Column: Usually a free-standing support, often cylindrical in shape.
Cornice: A decorative ridge or molding placed when the wall meets the roof.
Drum: A round wall supporting a dome.
Greek Cross: A church plan with four arms of equal length, also known as a centralized plan.
Impost Block: A square support block in the attic story.
Lantern: The top of a dome, usually a round turret-like steeple.
Latin Cross: A church plan with a long nave; the floor plan is in the form of a crucifix. The most common Christian church floor plan.
Nave: The long central hall of a church, from the entrance to the altar, where the pews are placed.
Pediment: A triangular or rounded motif usually above columns, but in St. Peter’s it appears above the dome windows, on the dome windows, and on the interior of the dome windows.
Pilaster: A flattened column, but attached to a wall, used more for decoration than structural support.
Ribs: Used in vaults and domes, a curved stone that projects outward to support and define the convex surface.
Sources
Bambach, Carmen C. Michelangelo: Divine Draftsman and Designer. Metropolitan Museum of Art, 2017.
Hemsoll, David. “The Laurentian Library and Michelangelo's Architectural Method.” Journal of the Warburg and Courtauld Institutes, vol. 66, 2003, pp. 29–62.
Hibbard, Howard. Michelangelo. Harper & Row, 2nd edition, 1974.
Wallace, William E. Michelangelo, God’s Architect: The Story of His Final Years and Greatest Masterpiece. Princeton University Press, 2019.
Wallace, William E. “The 2014 Josephine Waters Bennett Lecture: ‘Certain of Death’: Michelangelo’s Late Life and Art.” Renaissance Quarterly, vol. 68, no. 1, 2015, pp. 1–32.
Wallace, William E. Michelangelo: The Artist, the Man, and his Times. Cambridge University Press, 2010.