9
Why the Last Supper Fell to Pieces
The science of art remained Leonardo’s overriding concern throughout his life, the main force behind his paintings, the motivation for his technical experimentation, the reason he delved into other fields, from anatomy to hydraulics, geology, botany, mechanics, astronomy, and cosmology. It was also the main reason he never finished his paintings, or, if he did finish them, the reason they deteriorated soon after he had completed them.
The Last Supper is perhaps the saddest example of Leonardo pushing experimentation too far.
The Last Supper, one of the few paintings Leonardo ever completed, “started to fall into ruin” less than twenty years after he finished it. One charitable visitor commented that the cause was “the dump in the wall,” but even he conceded that perhaps it was “because of some other inadvertent causes.” By 1566 it “was nothing but a blurred stain,” and by 1584 it was “in a state of total ruin.” The cause of this ruin was Leonardo’s experimentation with a technique—fresco—that was wholly unsuited to achieving the optical effects he deemed necessary to move viewers.
The Last Supper was made for the refectory of the Milanese Dominican church of Santa Maria delle Grazie. Duke Ludovico had grown attached to this convent, and every Tuesday and Saturday he dined with the friars there, sitting at one of the tables lining the refectory’s walls, eating a frugal meal in silence, and listening to sacred readings. In 1492, he chose the church as his burial place and had Bramante redesign parts of it to accommodate his tomb. A couple of years later, Ludovico commissioned Leonardo to paint the Last Supper in the monastery’s refectory. We can infer that this occurred in late 1494, right after he blocked Leonardo’s work on the equestrian statues (the duke had changed his mind only a few years after he had eagerly commissioned the work), or in early 1495, around the time Vincenzo Bandello, the same Dominican who had attacked the idea of Immaculate Conception, was appointed prior of the convent.
Depictions of the Last Supper were commonly displayed in refectories, as it gave friars the impression they were partaking of Christ’s last meal. The size of Leonardo’s painting—about four and a half meters by nine meters (or about fifteen by twenty-nine feet)—was not at all typical, however. Given its dimensions, the work could not be painted on a separate panel, but only directly on the wall, in fresco, a technique Leonardo had never used before.
Leonardo was not pleased with this commission. It came to him as a consolation prize for the loss of the work he really wanted to complete, the monumental horse representing Ludovico’s father. But the duke had repurposed the metal set aside for the horse to forge cannons to help his father-in-law, the duke of Ferrara, fend off a military attack. Leonardo was gracious enough to at least pretend to understand: “[Of] the horse I shall say nothing because I know the times,” he wrote Ludovico, adding, “my life in your service. I hold myself ever in readiness to obey.” In his spare time, Leonardo kept working on a clay model of the horse, perhaps hoping the duke would change his mind. Ultimately, though, there was nothing Leonardo could do but follow his patron’s orders.
He would paint the Last Supper.
(This was an unfortunate but common occurrence for court artists. Even Michelangelo faced a similar situation a few years later, when Pope Julius II commissioned the artist to design his tomb, a monumental sculptural project the artist was eager to complete but had to abandon when the pope changed his mind. Instead, the pope commissioned Michelangelo to paint a ceiling, a project the artist loathed as he regarded painting inferior to sculpture. But like Leonardo before him, he embraced the commission, and his fresco painting—the Sistine Chapel ceiling—is considered a masterpiece of Western art.)
In spite of his initial reservations, Leonardo made the Last Supper a masterpiece of art as philosophy.
He set the painted scene in a fictional room that seemed to be seamlessly integrated with the real space of the refectory. In the painting, the light appears to be coming from the left, which is the side where the refectory’s real windows are placed. As a result, natural light seems to filter through the real windows and wash over both the refectory and the painted scene—in effect giving the friars the illusion of sharing the same light and glow of Christ and his disciples, as if they all were sitting in the same hall at the same time. But Leonardo also painted Christ and his disciples about fifteen feet above the friars’ heads. The Dominicans could never fully inhabit the same space as the sacred figures. They could look at them only from below and imagine themselves partaking of the same mystical meal by mentally elevating themselves to the level of the sacred figures.
Leonardo designed the fictive space of the Last Supper according to the golden ratio, as he had done in previous paintings, but placed Christ’s head at the exact center of the scene, rather than on the golden ratio’s focal point. During the last restoration, the hole for the nail Leonardo used as an anchor while drawing the architectural background with mathematical precision was rediscovered on Christ’s temple. Leonardo set Christ’s head against a bright blue sky using a unique—and hard to paint—backlight effect that he himself discouraged painters from adopting, but that he rendered marvelously. The other heads he placed against dark backgrounds, just as he always recommended.
His greatest innovation, though, was his reinterpretation of the story itself. He read Matthew’s account of the last meal Christ shared with his disciples before his Crucifixion (Matthew 26) and selected three distinct moments of the narrative, which he combined in one single image. One moment was the shock wave that traveled through the group right after Christ announced that “one of you will betray me.” Leonardo imagined different reactions to the news as the apostles asked, “Lord, is it I?” The second moment was when Christ shared bread and wine with his disciples, anticipating the ritual of the Eucharist. A third moment was when Christ revealed the identity of the traitor as the one “who dips his hand with me in the dish,” and Judas, portrayed dipping his hand in the plate in front of Christ, asks, “Is it I, Rabbi?” to which Christ replies, “You have said so.” Leonardo’s previous works, especially the Adoration and the Virgin of the Rocks, had prepared him well for this synthesis of events that occurred at different times.
Leonardo wrote a long note, which he possibly meant to include in his book on painting, detailing the apostles’ different reactions:
One, who was drinking and has left the glass back in its place, turned his head toward the speaker. Another [apostle] intertwined the fingers of his hand and with stern eyebrows turned to his neighbor; the other [man] with open hands shows the palms and raises his shoulders up to his ears and opens his mouth in astonishment; another [apostle] talks into the ear of the other, and he who is listening turns to him and lends him an ear, holding a knife in one hand and in the other the loaf of bread cut in half with that knife; the other [man] in turning while he holds a knife knocks over a glass on the table; the other places his hands on the table and looks on, another [man] breathes a mouthful, the other leans forward to see the speaker and shades his eyes with his hand; the other throws himself behind the one who leans forward and looks at the speaker between the wall and the man leaning forward.
For the twelve apostles around the dinner table, he returned to a sketch he had drawn and then discarded for the Adoration about fifteen years earlier. In that sketch, he had divided a large group of people into small groups of three or four, each group engaged in animated conversation. He returned to the sketch because it provided a clever way to break down a narrative composition that required many people—and that could easily suffer from diminished optical accuracy and emotional intensity—into smaller narratives that instead enhanced these qualities.
For individual apostles, he drew from his stock of sketches made from life. Many figures display the likenesses of people he knew. Some are portraits of Milanese courtiers we can no longer identify, with the exception of Bartholomew, who has the facial features of Leonardo’s friend Bramante.
In short, Leonardo had all the resources he needed to execute a successful painting.
What he had no experience with at all was the fresco technique itself—and for good reason, though not the reason one might expect.
Fresco painting, after all, was exceptionally well suited to large surfaces. It was quick, cheap, and durable. Florentine artists had mastered it over the centuries to great acclaim. Colors were applied to a wet layer of plaster, the intonaco, so that the colors were absorbed into the plaster itself (the word “fresco” comes from the Italian fresco, which means “fresh” or “wet”). Great fresco painters worked fast, before the wet plaster dried, as they could not correct their mistakes once colors were sealed within the wall. They applied wet intonaco only over the patch they were able to paint in a day—indeed, each patch was called a giornata, from the Italian word for “day.” If one looks carefully at Renaissance frescoes, one can detect the outline of each giornata joined to the next. Fresco painters did add details a secco—that is, on top of the sealed and dried colors—but they did so only rarely as they knew that a secco additions were extremely fragile and that sooner or later they peeled off.
In short, frescoes required discipline, speed, careful advance planning, and a tight work schedule.
No painting technique was less congenial to Leonardo’s philosophical art—or his working habits—than this one.
In frescoes, he could not add a touch here, another there; he could not apply a layer of glaze atop a thin layer of color, or use glaze mixed with a hint of a pigment to create blurred edges and nuanced color reflections. Leonardo had never felt the urge to learn fresco painting, even though some of the artists who had passed through Verrocchio’s workshop had become accomplished fresco painters: Botticelli, Perugino, Ghirlandaio. Now that he was asked to paint the Last Supper, he had to come to terms with fresco painting and its limitations.
Was it possible to paint a large mural as if it were a wood panel? No, it was not.
He tried to do so nonetheless.
Since the Adoration, Leonardo had prepared his panels using a bright layer of lead white so as to enhance the illusion that light came from within the work, as well as to add luminosity and modulation to the colors and varnishes he applied above. But lead white was not a good choice for murals, as it oxidizes in the presence of materials used to build walls and turns into a rather unappealing brownish color. Every art manual mentioned this, and every beginner fresco painter knew better than to apply lead white to a wall.
But Leonardo disregarded this long-standing advice. He added a thin layer of lead white mixed in oil to the rough plaster on the wall. It was his intention to use this as a sort of imprimitura to isolate the plaster from the colors he would apply above—in other words, he was not trying to produce a fresco so much as a traditional painting atop the unstable and highly imperfect surface of a wall—a mural painting instead of a panel painting. This was wishful thinking.
And there was more to come.
Although he knew that a secco touches are perishable and should be used sparsely, only for minor details, he applied them extensively. In fact, he did what every art manual recommended he not do: he painted one layer, waited for it to dry, and applied another on top of it. Often, he repeated this layering technique three or four times.
There was still more.
He used azurite and malachite to paint blues and greens, as he wished to obtain the brightest possible colors. But, as every Renaissance artist knew, particles of azurite and malachite do not mix well with the lime plaster found in walls, and should be avoided in frescoes at all costs.
To paint the way he wanted, he stretched the fresco technique to its physical limits. On a layer of lead white, he sketched with whatever drawing media he pleased—ink, thin black paint, black charcoal, red chalk. He corrected outlines, adjusted colors of garments, added glazes, and balanced shades and reflections.
Truth be told, when he painted transparent and metal objects, such as glasses, dishes, and cutlery, and their delicate reflections and refraction, he painted images that had never before been seen on a wall. Richness of colors, balance of shades and reflections, transparent glasses, reflective metal surfaces: all those optical effects that were impossible to render with traditional fresco colors made Leonardo’s Last Supper unique.
But the real reason he looked for ways to make fresco painting more malleable had to do with his desire to capture the essence of each of the apostles. He had created for them unique body motions that were appropriate for the scene but that also foretold the destiny of each. Peter, on the far right, holds a knife, which is more than a dining utensil—it is a reference to a gruesome event that happened right after the supper, which is recounted in the Bible: to defend Christ, Peter cut off the ear of a servant. Peter’s knife points toward Bartholomew in what seems like a casual manner, but it is likely a reference to Bartholomew’s death as a martyr by flaying. Similarly, Thomas (he is painted next to Christ) raises his finger to the sky in a gesture Leonardo favored, but which is also a pointed reference to his later encounter with Christ, when he stuck that same finger in Christ’s chest wound out of doubt (Verrocchio’s bronze statue for Orsanmichele showed the same story). John (also seated next to Christ) leans on the table with his hands clasped and his fingers intertwined, a gesture that anticipates how he grieved at the foot of the cross, as depicted by Renaissance painters. Judas holds a money bag, which is a clear reference to how he betrayed Christ for money; his neck displays pronounced muscles, which were associated with criminals in the Renaissance, and his face is in shadow. A beautiful drawing of Judas in red chalk is among the few preparatory drawings that has survived (Figure 11); it gives us a sense of the intensity of Leonardo’s figures, a quality that has largely been lost owing to degradation of the mural.
Leonardo worked slowly and deliberately. We know this because Prior Vincenzo Bandello had a young nephew, Matteo Bandello, who lived at Santa Maria delle Grazie and who had the good fortune to be able to watch Leonardo at work. It is in turn our good fortune that young Matteo wrote down what he saw, providing an eyewitness account of Leonardo’s idiosyncratic, unscheduled way of painting:
Many times he used to go—and I witnessed him to do this quite often—in the very early morning, climb the scaffolding, because the Last Supper is high off the ground, he would—I say—not put down the brush in his hands from sunrise till the shades of evening, forgetting to eat and drink, he would continuously paint. Then there would be two, three, and four days in which he would not touch the work with his hand, but he would stay for one or two hours of the day only to contemplate, consider, and examine his figures in solitude, in order to judge them. I would also see him, as the whim or fancy touched him, leaving at midday, when the sun reached its zenith, from the Corte Vecchia where he was making that stupendous [model of the] horse in clay, and come straight to the Grazie, climb on the scaffolding, seize the brush, give one or two brushstrokes to a figure, and then suddenly depart to go elsewhere.
The sight of Leonardo at work became something of an attraction. Many came to the refectory to watch. They stood there in complete silence, or at most whispering “with hushed voices,” as if they were attending a religious function rather than watching an artist at work. But it was a genius at work they had come to watch, one who pondered every stroke of his brush as each changed the optical balance of the whole work. The Last Supper was already widely admired even before Leonardo finished it, probably around 1497–1498. His friend Luca Pacioli praised it for the emotions it portrayed. The mural was
an exquisite image of humans’ burning desire for salvation, in which it is not possible to imagine the apostles responding more, even when they were alive, to the sound of the infallible voice of truth, as it said: “Unus vestrum me traditus est” [One of you will betray me]. With acts and gestures turning from one to the other, and from the other to the one, and with vivid and pained astonishment, they seemed to speak to one another. With his [elegant] lightness of touch, our Leonardo most worthily designed it so.
The French monarch Louis XII, who had become the ruler of Milan after Ludovico, wanted to detach the Last Supper from the wall and take it to Paris. The operation proved to be impossible, and the mural remained in the refectory.
But Leonardo’s extreme technical experimentation in painting meant that, after less than twenty years, the mural was a ghost of its former self.
Leonardo’s a secco touches peeled off.
Azurite and malachite lost their brightness and also peeled off.
The other colors were distorted by their reactions with the lime plaster.
The science of art that had been the reason for its success was also the reason for its ruin.
Over the centuries, various restoration efforts tried to slow the decay, but there was not much that could be done to halt or reverse the slow-motion disaster.
It is estimated that only about 20 percent of what we see today can be attributed to Leonardo’s hand—the rest is the work of later restorers. And yet, thanks especially to those who conducted the last restoration, from 1977 to 1997, and who pushed restoration techniques to their physical limits, we can still sense Leonardo’s skill at rendering the faces of the apostles, the pleats of the tablecloth, the metal dishes, the transparent glasses.
Leonardo would paint on a wall only one other time. It was in Florence, where he returned after the French takeover of Milan. After enduring the humiliation of seeing his clay model for Ludovico’s horse used as a target by French bowmen, he grimly summed up his twenty years at the Milanese court: “the duke lost his duchy and his things and his freedom and none of the work I planned for him was carried out.” On December 14, 1499, he transferred six hundred ducats to a bank in Florence, which was the revenue he got from a vineyard Ludovico had given him as a gift in 1498 (Salai would inherit this vineyard after Leonardo’s death). Shortly thereafter he left Milan. He made brief stops in Mantua and Venice, and by the spring of 1500 he was in Florence.
The city had gone through major political changes. Lorenzo de’ Medici had died in 1492, his son Piero was inept at keeping the family in control of Florentine politics, and the Medici were expelled in 1494. The Dominican friar Girolamo Savonarola ruled for a few years, proclaiming a republic ruled by the people in the name of Christ. To gather the five hundred citizens who were supposed to rule the city, Savonarola created a large audience hall in the Signoria palace, which came to be known as the Sala dei Cinquecento, or Hall of the Five Hundred. By 1498, Savonarola had lost his popular support and was burned at the stake. Machiavelli became the chancellor and created a new position: the standard bearer of justice for life, or gonfaloniere di giustizia a vita, to which he managed to have his friend Piero Soderini elected in 1502. Soderini was as acutely aware of the power of art as the Medici had been in previous decades. One of his first official acts was to ask Leonardo to paint a large fresco for the Hall of the Five Hundred that celebrated the Florentine republic.
At the size of eight by twenty meters, the mural was twice as wide as the Last Supper. Its subject was equally grand: the Battle of Anghiari, which the Florentines won against Milan thanks to a cloud of dust and smoke that alerted them to the impeding attack. “You must first represent the smoke from the artillery, mingled in the air with the dust stirred up by the movement of the horses and the combatants,” Leonardo wrote in a passage he possibly intended to include in his book on painting. Thinking more like a physicist than an artist, he explained in the same passage that dust is made of particles of different weights: the finest particles, which get to the highest reaches, mingle with air and acquire its color; heavier particles stay closer to the ground, mingling with smoke and acquiring “the appearance of a dark cloud.” And while dust mixes with smoke, the color of this mixture is different: it is “much more luminous” when seen from the side of the light source than from the opposite side. But “in the midst of the swirling mass […] of foam, and water exploding into the air and among the legs and bodies of the horses,” the mixture displays “less difference between light and shadows.” The dust generated by galloping horses also looks different depending on where the animals are: those that are more distant from the viewer create clouds of dust that are “thinly spread out” and minimally visible, but horses that are closer make clouds that are “more noticeable, smaller, and more tightly packed.”
Leonardo’s battle scene did not look like a traditional fight among mounted soldiers. The violence was not conveyed by the fight itself but by the thickness of a cloud made of dust, smoke, and blood, mixed with light and shadow: a denser cloud meant a more frenzied clash “in the midst of the swirling mass.” His writings on dust and smoke, light and shadow, recall Alhacen’s treatment of optical science in their style.
Leonardo went one step further in his written treatment of the battle scene. For him, the representation of a battle demonstrated the superiority of painting over poetry, a topic he intended to address in his book on painting:
If you, poet, were to portray a bloody battle you would write about the dark and murky air amid the smoke of fearful and deadly engines of war, mixed with all the filthy dust that fouls the air, and about the fearful flight of wretches terrified by awful death […] Your tongue will be impeded by thirst and your body by sleep and hunger, before you could show in words what the painter may display in an instant.
Like the Last Supper, this battle scene had to be painted in fresco. And the results, sadly, were just as disastrous, perhaps even more so. There is nothing left of Leonardo’s Battle of Anghiari.
Leonardo did create a highly detailed, fully finished cartoon, a ben finito cartone, that consumed over four hundred sheets of royal paper, or carta reale; he made a copy of it, which he colored and brought to the Signoria palace for transfer to the wall. By June 6, 1505, he was painting—but as Leonardo himself reported, that day things took a wrong turn “at the very moment of laying down the brush.” The weather deteriorated. A jar broke. Water spilled. Rain poured in in great quantities. “It was as dark as night” and “the cartoon tore.” People in the Renaissance believed transformational events were marked by exceptional natural occurrences. The storm that erupted that day and tore the cartoon was a bad omen for Leonardo’s Battle of Anghiari.
To make matters worse, when Leonardo was in the midst of his preparatory work, the twenty-nine-year-old Michelangelo was asked to paint another battle scene next to Leonardo’s. It was almost like a vote of no confidence in Leonardo’s ability to deliver the mural.
Leonardo never finished his battle, and, for that matter, neither did Michelangelo finish his. Allegedly, they did not complete their respective battles because they both left Florence—Michelangelo for Rome, Leonardo for Milan. For brief periods they were in Florence at the same time, but by and large they avoided each other and made a point of leaving a city when the other was around, no matter what the city was. But from their rivalry came two cartoons that were regarded as la scuola del mondo, everybody’s school. Generations of artists flocked to learn from them in the halls where they were kept, until they were completely torn into pieces and lost. Today, we know about these two battle scenes thanks only to copies by later artists.
Fresco, then, was most certainly not Leonardo’s preferred medium, even though the demands of patrons and the contingencies of specific commissions forced him to use the technique. Because he was such a great experimenter, he tried to bend it to suit his artistic needs—namely, the need to retouch a work endlessly as every new brushstroke changed the optical balance of the whole. Others—Michelangelo and Raphael—would become the great fresco painters of the sixteenth century. We have only to think about the great fresco cycles they painted in the Vatican just a few years after Leonardo abandoned his Battle of Anghiari, and when his Last Supper was already showing signs of decay. The ceiling of the Sistine Chapel and the Last Judgment on its altar wall, the Vatican Stanze, the Loggias, the Pauline Chapel—those were the great frescoes of the Renaissance, all done for popes at the Vatican.
As for Leonardo, he moved in a different direction. He came to value excellence of execution over everything else: “Excellent painters,” he wrote, “will produce few works, although these will be of such quality that men will stop in admiration to contemplate their perfection.” But excellent painters are never satisfied: “when the judgment disdains the work this is a perfect sign.” He came to value his own critical thinking over the completion of a finished product. Whether it was a painting, a book, or an experiment, it was the process rather than the outcome that mattered to him.