by The Science of Leonardo: Inside the Mind of the Great Genius of the Renaissance
The words of Christ have stirred up the solemn company, creating powerful waves of emotion. However, the effect is far from chaotic. The apostles are clearly organized into four groups of three figures, with Judas forming one of the groups together with Peter and John. This is another striking compositional innovation. Traditionally, Judas was pictured sitting on the other side of the table, facing the apostles, with his back to the spectator. Leonardo had no need to identify the traitor by isolating him in this way. By giving the apostles carefully chosen expressive gestures, which together cover a wide range of emotions, the artist made sure that we immediately recognize Judas, as he shrinks back into the dark of John’s shadow, nervously clutching his bag of silver. The depiction of the apostles as embodiments of individual emotional states and the integration of Judas into the dramatic narrative were so revolutionary that after Leonardo, no self-respecting artist could go back to the previous static configuration.
Throughout his career as a painter, Leonardo was famous for his ability to capture emotional subtleties—the “movements of the soul”—in facial expressions and eloquent gestures, and to weave them into complex compositional narratives. This exceptional ability was already apparent in his early Madonnas and reached its climax in The Last Supper and his other mature works.
The playwright and poet Giovanni Battista Giraldi, whose father knew Leonardo, provided a fascinating glimpse of the artist’s methods in achieving this singular mastery. “When Leonardo wished to paint a figure,” Giraldi wrote, “he first considered what social standing and what nature it was to represent; whether noble or plebeian, gay or severe, troubled or serene, old or young, irate or quiet, good or evil; and when he had made up his mind, he went to places where he knew that people of that kind assembled and observed their faces, their manners, dresses, and gestures; and when he found what fitted his purpose, he noted it in a little book which he was always carrying in his belt. After repeating this procedure many times, and being satisfied with the material thus collected for the figure which he wished to paint, he would proceed to give it shape.”8
During this period, while Leonardo painted The Last Supper and meditated on the nature of human frailty and betrayal, his personal life was enriched by an encounter that would turn into a lasting friendship. In 1496 the Franciscan monk and well-known mathematician Luca Pacioli came to teach in Milan. Fra Luca had established his reputation as a mathematician with a vast treatise, a kind of mathematical textbook, titled Summa de aritmetica geometrica proportioni et proportionalità (Summary of Arithmetic, Geometry of Proportion, and Proportionality). Written in Italian rather than in the customary scholarly Latin, it contained synopses of the works of many great mathematicians, past and present. Leonardo, who had been keenly interested in mathematics since his studies at the library of Pavia, was fascinated by Pacioli’s treatise and immediately attracted to its author.
Fra Luca was a few years older than Leonardo and a fellow Tuscan, which may have helped them establish an easy rapport that soon turned into friendship. This friendship gave Leonardo a unique opportunity to deepen his mathematical studies. Pacioli not only helped him understand various portions of his own treatise, but guided him in a thorough study of the Latin edition of Euclid’s Elements. With the help of his friend, Leonardo systematically worked through all thirteen volumes of Euclid’s foundational exposition and filled two Notebooks with mathematical notes.9
Soon after they began their study sessions, Leonardo and Fra Luca decided to collaborate on a book, titled De divina proportione, to be written by Pacioli and illustrated by Leonardo. The book, presented to Ludovico as a lavish manuscript and eventually published in Venice, contains an extensive review of the role of proportion in architecture and anatomy—and in particular of the golden section, or “divine proportion”—as well as detailed discussions of the five regular polyhedra known as the Platonic solids.10 It features over sixty illustrations by Leonardo, including superb drawings of the Platonic solids in both solid and skeletal forms, testimony to his exceptional ability to visualize abstract geometric forms. What further distinguishes this work is that it is the only collection of drawings by Leonardo published during his lifetime.11
While Leonardo drew the illustrations for Pacioli’s book, he also continued work on The Last Supper. Progress was steady but slow, as the artist worked on in his typical thoughtful and meditative way. He spent considerable time roaming the streets of Milan looking for suitable models for the faces of the apostles.12 By 1497 the only part left to complete was the head of Judas.13 At that point, the prior of the convent became so impatient with Leonardo’s slowness that he complained to the duke, who summoned the artist to hear his reasons for the delay. According to Vasari, Leonardo explained to the Moor that he was working on The Last Supper at least two hours a day, but that most of this work took place in his mind. He went on, slyly, to say that, if he did not find an appropriate model for Judas, he would give the villain the features of the petulant prior. Ludovico was so amused by Leonardo’s reply that he instructed the prior to be patient and let Leonardo finish his work undisturbed.
A few months later The Last Supper was completed. Unfortunately, it soon began to deteriorate. The painting is not a fresco, strictly speaking; it was not painted al fresco with water-based pigment on damp, fresh plaster. The fresco technique resulted in lasting murals but required fast execution, which was incompatible with Leonardo’s way of painting. Instead, the artist experimented with a mixture of egg tempera and oil. Because the wall was damp, the painting soon began to suffer. Tragically, subsequent attempts to halt or reverse its deterioration have been unsuccessful. Over the centuries there have been countless restorations of The Last Supper, many involving questionable techniques and often without exact records being kept. As Kenneth Clark wrote in 1939, “It is hard to resist the conclusion that what we now see on the wall of the Grazie is largely the work of restorers.”14
The last effort to restore Leonardo’s masterpiece, completed in 2000 under the direction of Pinin Brambilla Barcilon, was by far the most elaborate and sophisticated, taking more than twenty years.15 The restorer and her team removed almost all the traces of earlier restorations in order to expose as much of Leonardo’s paint as could be found. Instead of concealing the damage, they reconstructed the original contours and filled the empty spaces between the existing fragments with watercolor of the same general hue. What the spectator now sees from a close distance are clear distinctions between the original paint and the empty spaces, while from farther back these distinctions disappear, giving way to the impression of seeing a faded version of the original painting.
In spite of the fact that very little is now left of Leonardo’s original masterpiece, the restored work does show the eloquence and power of the protagonists’ gestures, and even a hint of the luminosity that is so characteristic of Leonardo’s paintings. “We still catch sight of the superhuman forms of the original,” writes Kenneth Clark, “and from the drama of their interplay we can appreciate some of the qualities which made The Last Supper the keystone of European art.”16
POLITICAL TURMOIL
When Leonardo finished The Last Supper in 1498, he did not know that his position at the Sforza court and his stay in Milan would come to an abrupt end two years later. His study and research program continued unabated. He kept up his mathematical studies with Fra Luca, worked on the theory of human flight, and experimented with various flying machines. In addition, he painted a portrait of Ludovico’s new mistress, Lucrezia Crivelli,17 and after the tragic death of the duke’s wife Beatrice, Ludovico entrusted him with the decoration of the Sala delle Asse in her memory.18
In those last two years at the Sforza court, Leonardo also made several journeys within northern Italy. In 1498 he accompanied the Moor on a visit to Genoa, and on another occasion he made a trip to the Alps. There, he climbed the Monte Rosa,19 Europe’s second-highest mountain, a huge glacier-covered massif at the Swiss-Italian border with ten major pe
aks, most of them higher than 4,000 meters (13,000 feet). Even today, ascending any one of these peaks is very strenuous, although technically not difficult, involving five to ten hours of climbing up steep grades, and walking long stretches on glaciers. One has to be in good physical condition, accustomed to high altitude. In Leonardo’s time, such an ascent must have been extraordinary.
Several of his contemporaries describe Leonardo as being very athletic in his youth;20 clearly, he still had the necessary strength to climb mountains in his forties. In his notes he describes the deep blue of the sky “almost above the clouds,” and the silvery threads of rivers in the valleys below. The view from that height, several hundred years before the age of industrial pollution, must have been spectacular indeed. He could see the “four rivers that water Europe”—the Rhine, the Rhône, the Danube, and the Po.21
While Leonardo enjoyed the clear view of the valleys and rivers from Monte Rosa, political clouds threatening the peace were gathering. In 1494 the king of France, Charles VIII, crossed the Alps at the head of a large army; Ludovico sacrificed the bronze retained for the casting of Leonardo’s gran cavallo in order to defend Milan.22 During the subsequent years, the French steadily advanced through Italy. In 1498, after Charles VIII died in an accident, the new French king, Louis XII, declared himself duke of Milan and prepared to conquer the city.
In the summer of 1499, Louis formed a secret alliance with Venice and invaded Lombardy to attack its capital, Milan, while the Venetians attacked from the east. Ludovico, in panic, fled to Innsbruck, Austria, with his family to seek the protection of his relative, Emperor Maximilian. In September, Milan capitulated without a shot being fired.23 Leonardo, apparently quite oblivious to the political turmoil around him, calmly recorded some new observations on “movement and weight” in his Notebooks.24
In October, Louis XII entered Milan in triumph. Apparently, he offered Leonardo a position as military engineer. Louis was so enchanted by The Last Supper that he inquired whether it could be removed from the wall of the Grazie and taken to France.25 Leonardo, however, turned down the king’s offer, perhaps because he had witnessed widespread looting and killing by the French troops. When a detachment of archers used the clay model of his cavallo for target practice, he realized it was time for him to leave the city. He put his affairs in order, sent his savings to his bank at Santa Maria Nuova in Florence, and before the year was out, he and his friend Fra Luca left Milan.
RETURN TO FLORENCE
Luca Pacioli traveled directly to Florence; Leonardo made a long detour via Mantua and Venice and joined his friend a few months later. When he returned to Florence, where he would spend the next six years, Leonardo, now forty-eight, was at the beginning of what was then considered old age. However, his artistic and scientific creativity continued undiminished. Over the next fifteen years he would paint several more masterpieces and produce his most substantial scientific work. He was now famous as an artist and engineer throughout Italy. And it was well known by his contemporaries that he dedicated much of his time to scientific and mathematical studies. The fact that hardly anyone knew what those studies were about only enhanced his image as an enigmatic genius.
Leonardo was in great demand as a consultant in architecture and military engineering as well as for lucrative commissions for paintings. Having been paid handsomely by Ludovico Sforza for the past decade, he had enough financial security that he did not have to curry favor with the powerful and wealthy, even though steady and lucrative employment was his preference. However, he continued to be utterly aloof from politics, and showed little loyalty to any state or political ruler.
Many of Leonardo’s consulting assignments, especially those in military engineering, required him to travel to other cities in northern Italy, and his second period in Florence was punctuated by frequent journeys. But his travels seemed to inspire him to ever more intense work. In addition to examining military fortifications and producing numerous drawings with suggestions for improvements, he studied the flora and geological formations of the areas he visited, drew beautiful, detailed maps that showed distances and elevations, and visited renowned libraries to continue his theoretical studies.
Leonardo’s maps from that period show geographical details with a degree of accuracy far beyond anything attempted by the cartographers of his time.26 He used washes of different intensities to follow the contours of mountain chains, different shades representing different elevations, and he pictured the rivers, valleys, and settlements in such a realistic manner that one has the eerie feeling of looking at the landscape from an airplane (see Fig. 7-7 on Chapter 7). In most of his maps, Leonardo focused specifically on the network of rivers and lakes. In some views of stretches of the river Arno (Fig. 4-1), he uses blue wash of varying hues to produce a striking resemblance between the flow of the river’s watercourses and the flow of blood in the body’s veins (Fig. 4-2)—an exquisitely beautiful and moving testimony of how Leonardo saw water as the veins of the living Earth.
Leonardo also continued to create great artistic works (including the Madonna and Child with the Yarnwinder, various sketches for the Madonna and Child with Saint Anne, and two different compositions for Leda and the Swan), many of which exerted considerable influence on contemporary painters, including Raphael and Michelangelo.27 “Surprisingly,” writes Martin Kemp, “this period is marked by an astonishing richness of artistic activity, in which more than a dozen significant compositions were conceived and taken to various stages of completion by Leonardo himself or his assistants.”28
Figure 4-1: The water veins of the Earth, river Arno, c. 1504, Drawings and Miscellaneous Papers, Vol. IV, folio 444r
In February 1500, soon after leaving Milan, Leonardo spent a few weeks in Mantua at the invitation of Isabella d’Este, the elder sister of Ludovico’s late wife Beatrice. Beautiful and sophisticated, Isabella was a renowned art collector and generous patron of the arts, if temperamental and tyrannical.29 She was mainly interested in paintings that praised her merits and would often dictate their composition, even the colors to be used. It was well known how she had harassed Giovanni Bellini, taking him to court to obtain exactly the picture she wanted, and how she had written no fewer than fifty-three imperious letters to Perugino, pressing him to finish an allegory she had designed.
Figure 4-2: Blood veins in the left arm, c. 1507–8, Anatomical Studies, folio 69r
Isabella had met Leonardo often at the Sforza court and had always beseeched him to paint her portrait. In Mantua, the artist seemed to obey. He drew her in profile in black and red chalk and probably also offered her a copy, implying that he would keep the original in order to transfer it to a panel and paint it later.30 However, in spite of many subsequent entreaties by Isabella’s emissaries, Leonardo never painted the full portrait. Apparently, he had no desire to subject himself to Isabella’s whims. Beneath his exquisite courtesy and charm, he always remained fiercely independent when his artistic integrity was at stake.
From Mantua, Leonardo journeyed to Venice, where the Senate was in urgent need of a military engineer with his talents. The Venetians had just suffered a defeat in a naval battle against the Turks. And the Ottoman army was encamped in the Friuli region on the banks of the river Isonzo, threatening an invasion from the republic’s northeastern borders. Leonardo went to Friuli, studied the topography of the land, and came back to the Senate with a plan to build a movable lock on the Isonzo. He argued that this could be used to dam up a large body of water, which could be released to drown the Turkish armies when they crossed the river.31 Ingenious as the plan was, the Venetian Senate rejected it.
The Venetians were also concerned about a possible attack by the Turkish navy. Leonardo responded to this challenge with designs of diving apparatus, invisible from the surface, to be used in marine warfare—small submarines that could be sent out “to sink a fleet of ships” divers equipped with airbags, goggles, and special devices to bore holes into the planks of ships; frogmen with flippers,
and the like. The modern look of these designs is quite astonishing.32 Leonardo was well aware of the conflict between his work as a military engineer and his pacifist nature.33 “I do not describe my method for remaining under water for as long as I can remain without food,” he wrote in the Codex Leicester. “This I do not publish or divulge because of the evil nature of men, who might practice assassinations at the bottom of the seas by breaking the ships in their lowest parts and sinking them together with the crews who are in them.”34
Leonardo was also asked to examine the Venetian canal system for possible improvements. In the course of this work, he invented a beveled lock gate that played a part in the evolution of canal design.35 In view of all these interesting projects in civil and military engineering, it is surprising that Leonardo did not stay in Venice for more than a few weeks. Yet, by April 1500, he was back in his native Tuscany.
The most likely explanation for his quick return to Florence is that Luca Pacioli had, in the meantime, been awarded the chair of mathematics at the University of Florence. Leonardo must have seen it as an ideal opportunity for him to continue his studies with Fra Luca, and to meet leading Florentine intellectuals. Besides, he was also likely looking forward to being appreciated as an artist in the city that had nurtured his genius in his formative years.
Leonardo’s expectations of a warm welcome in Florence were amply met. Soon after his arrival in the city, he was invited to paint an altarpiece for the Servite convent of the Santissima Annunziata. To make the commission more attractive, the friars provided spacious lodgings for Leonardo and his household in the convent’s guest quarters.36 Leonardo gladly accepted the commission and took up residence in the Annunziata, although he kept them waiting a long time before starting the commission. Instead of painting, he calmly pursued his mathematical studies with Pacioli and continued his experiments on weight, force, and movement.
