IF YOU LOOK AT A map of sixteenth-century Milan, the Castello Sforzesco seems to have inflated the whole city, which spreads around it like the expanded cheeks of a frog. Duke Ludovico Sforza’s fortress-cum-palace stood on one edge of the town, a hexagon surrounded by strikingly tall, elegant brick walls. In the surrounding piazza you could sometimes see the duke’s monkeys scampering about in special Sforza uniforms. A constant stream of diplomats and officials, supplicants and servants, poured in and out of the palace gates, and among the courtyards and buildings inside. The smooth stone staircases were so long that women sometimes rode horses up them, to avoid tiring their legs. Eight hundred people lived within the walls. In their secluded apartments, the duke and his wife slept under silk veils designed to protect their dreams.
The duke was known for his extravagant parades and ceremonies, celebrating the arrival of an ambassador, a family marriage, the election of a pope, or a military victory. On one such occasion—for the entrance of his wife into the city—there was a procession of nearly five hundred horses, representatives of thirty-six different orders of priest, sixty knights, and fifty ladies, accompanied by sixty-two trumpets, along a route covered in white fabric leading from the castle to the cathedral. Along the way, the walls were covered with tapestries and garlands of juniper and orange blossom. The Florentine ambassador observed that “everything was so well organized that there was not even the slightest trouble in the street, which is no small thing, because the crowds in this city are enormous.”
The duke attracted a cross-section of Italy’s leading artists and scholars to his court with stipends and commissions, and he expected something in return: an obsequious chorus of great intellects and imaginations celebrating his transition from ruthless military commander to man of arts and letters. The court poet Bellincioni wrote in hackneyed verse that Milan was Athens and Parnassus,*1 presided over by the “divine” Ludovico Sforza, “a guide, a star.”
The highest pinnacle an artist could reach in Renaissance Europe was to be appointed court artist, a position conferred on Leonardo by the Duke of Milan by 1490. There were now many other pressures on his time aside from painting. The court valued his skills as a set designer and entertainer as highly as his abilities as a painter. He played the lira da braccio, a forerunner of the violin; he entertained gatherings with riddles, jokes, and cryptic prophecies; he took part in ritualized philosophical debates in which scholar-courtiers discussed which art was superior, painting, music, or poetry—painting, Leonardo always argued. He worked as an interior designer, decorating rooms in the palace, including the spectacular Sala del Asse, “the Hall of the Wooden Boards,” which he transformed into a forest of mulberry trees whose canopy of leaves and branches covered the ceiling in knot-like patterns.
Leonardo combined his skills as an artist and engineer to stage spectacles with dramatic transformations and moving parts. In one he created a vision of Paradise that, a member of the audience noted, “was made to resemble half an egg, which from the edge inwards was completely covered with gold, with a very great number of lights representing stars, with certain gaps where the seven planets were situated, according to their high or low ranks.” Inside the egg, many singers performed “accompanied by many sweet and refined sounds.”*2 One can imagine that it would have looked like a living Leonardo painting as actors, often members of the court, in elaborate costumes awkwardly recited classical myths, chivalric codes of honor, and contrived allegories to flatter the duke and his guests.
For another, Leonardo designed elaborate decorations for a horse. The Duke of Milan’s secretary Tristano Calco gave an eyewitness account of this sight: “First a wonderful steed appeared, all covered with gold scales which the artist has colored like peacock eyes…the head of the horse was covered with gold; it was slightly bent and bore curved horns.” Astride the horse was a rider, from whose “head hung a winged serpent, whose tail touched the horse’s back. A bearded face cast in gold looked out from the shield.”*3
Leonardo was staging such shows for the French rulers of Milan at the Castello Sforzesco between 1506 and 1513, when the Salvator Mundi was on an easel in his studio. His biographer Paolo Giovio was at court at this time, and wrote how Leonardo “was a marvelous inventor and arbiter of all elegance and theatrical delights.” He drew sketches for a stage set of a range of mountains, which were to open—as he wrote next to the design drawing in his notebook—by means of pulleys, ropes, and weights to reveal a large cave, where “Pluto is discovered in his residence,” along with Cerberus, devils, furies, and “many naked children.” In 1515 a mechanical lion designed by Leonardo was the star attraction in a pageant for the young French king Francis I. Another Leonardo biographer, Gian Paolo Lomazzo, tells how the lion “moved from its place in the hall and when it came to a halt its breast opened, and was full of lilies and other flowers.”*4 The lion was a symbol of Florence, the lilies a symbol of the French monarchy, so the ensemble represented the new alliance between the two powers.
The constant stream of entertainment, engagements, and commissions from the court left Leonardo little time to paint. And even when he wasn’t dragooned into designing events for Milan’s rulers, he did not immediately pick up his brush; he had better things to do. From the mid-1480s, when he was already past the age of thirty, he began a campaign of self-education across the fields of the arts and sciences, which included teaching himself Latin, in a self-conscious effort to elevate himself from artisan to intellectual.
He built up a substantial library for his time. He owned 40 books by 1492; by 1503, 116. On his shelves you would find biographies of the philosophers, texts on mathematics, military science, agriculture, surgery, law, music, precious stones, health and palm-reading, grammar and rhetoric, travelogues, Aesop’s fables, Ovid, Livy, Petrarch, Aristotle, Archimedes, Euclid, Ptolemy, psalms, and the Bible. Among his great friends at this time was the mathematician Luca Pacioli. Leonardo drew illustrations of geometrical forms and knots for Divina Proportione, one of Pacioli’s books on mathematics, and Pacioli thanked him for his “invaluable work on spatial motion, percussion, weight and all forces.”
In the 1490s, Leonardo began to fill his notebooks. Occasionally he wrote lists of people he wanted to consult. In one of these, dated to 1495, he scribbled, backward as usual, “Ask Maestro Antonio how mortars are positioned on bastions by day or night; Ask [Medici banker] Benedetto Portinari by what means they go on ice in Flanders; get the master of mathematics to show you how to square a triangle; find a master of hydraulics and get him to tell you how to repair, and the costs of repair of a lock, canal and mill in the Lombard manner.” Leonardo was open-minded and receptive, adept at drawing on the skills of others and absorbing their knowledge.
This is all to say that, after 1500, the focus of Leonardo’s interests turned decisively away from painting. His preoccupation with mathematics, the natural sciences, and technology consumed him. Fra Pietro da Novellara visited him in 1501 and reported back to his employer Isabella d’Este that “he devotes much of his time to geometry, and has no fondness at all for the paintbrush.” Leonardo believed that everything came down to mathematics, writing that “he who defames the supreme certainty of mathematics feeds on confusion.”
And he recorded it all. He covered thousands of pages of paper with drawings of basic machines, anatomical studies—he famously dissected the corpse of a centenarian—mathematics, optics, and geometry. His notebooks contain references to two hundred species of plants and over forty varieties of trees. They are dotted with questions, as he sought to articulate the physical laws for all manner of natural phenomena. “Why does a solitary rock in the level of a stream cause the water beyond to form many protuberances?” he asked himself on one occasion. On another he posed the question: “Why do dogs willingly sniff one another’s bottoms?” He came to the wrong conclusion: “The excrement of animals always retains some essence of its origin…If by means of the smell they know a dog to be well fed, they respect him because he has a powerful and rich master; and if they discern no such smell of that essence [i.e., of meat] they judge the dog to be of small account, and to have a poor and humble master, and therefore they bite him.”
Leonardo’s empirical approach to understanding the world was a striking break from the past. His central tenet, that “all our knowledge has its origins in our perceptions,” derived, admittedly, from Aristotle, but the artist-engineer combined it with a new commitment to experiment, in which general laws were tested: “First you must explain the theory, then the practice.”*5
Among the instruments Leonardo invented were proportional compasses and tools for drawing parabolas and for constructing parabolic mirrors. He was a brilliant technical illustrator: the first engineer to draw architecture from the standard viewpoints of plan and perspective, and the first to draw exploded diagrams, so one could see how the parts fit together. His anatomical drawings were far in advance of his contemporaries in their accuracy and clarity, and were still used by doctors and biologists centuries later. He was the first astronomer to perceive that the gray color of the moon is caused by the light of the sun reflected off the earth’s oceans.
Leonardo’s notes were intended for publication. He planned treatises on anatomy, hydraulics, and the elements of machines, as well as painting, but he never got to the editing stage. None were published in his lifetime, and the only one published after his death was on painting. The historical orthodoxy is that Leonardo was a prophetic genius, who conceived of countless modern inventions before the science and technology existed to realize them. But he was more human than that. There are subjects he struggled to understand. There are rabbit holes. There is the sense of a quest that never reaches its destination.
Much of the time, Leonardo is less a genius than a determined student. He paraphrases the histories of art written by other Renaissance art theorists such as Alberti and Ghiberti. He obsesses over geometry. He struggles with algebra and with Latin vocabulary. He engages in long-prevalent scientific fantasies. It is said that he invented the parachute with a sketch, dated around 1485, of a four-sided pyramid covered in linen, attached to which “a man…can jump from any great height whatsoever without injury.” Yet others before him had had the same idea—in Spain in 852, in Constantinople in 1178, and at various times in China, as well as at least one of his Italian contemporaries, the mathematician Ignazio Danti from Perugia. His analysis of the flight of birds and the way their wings worked was close to that found in medieval treatises on falconry.*6 The analogies he drew between the earth and the human body, and between tides, breathing, and the circulation of blood, all had precedents in medieval scholarship. Many of his rules are, as the Russian Leonardist Vasily Zubov pointed out, personal observations rewritten as formulae.
The military technology and hardware that Leonardo boasted he could offer the Duke of Milan—the great guns, mortars, and chariots—were, so far as we know, never manufactured. Leonardo was a dreamer, a doodler, and a dawdler.
His aspirations were marked by their grandiosity. He developed plans for a canal from Florence to the sea by diverting the River Arno, calculating that a million tons of earth would need to be moved, a task that would take 54,000 man-days. He drew designs for various machines to partially mechanize the digging, though these were never manufactured. In fact, in 1504 work on the diversion of the Arno began, but without Leonardo’s participation. The project was a failure, many workers perished, and within only two months the project was abandoned. A few years later Leonardo designed a beautiful villa for the French governor of Milan, Charles d’Amboise. It would have a landscaped garden with little classical follies, islands with temples, and a water-powered windmill with huge sails that would work as a giant fan and keep the French elite cool in summer.*7 This was also never built. All we know for certain is that he designed and constructed an elaborate scaffolding platform that he could raise and lower to paint the huge fresco The Battle of Anghiari, and he was able to realize his plans for the renovation of the plumbing and sewers of the San Salvatore dell’Osservanza church in Florence. Such were the concrete engineering achievements of the “universal genius.”
All these scientific interests meant Leonardo did not have much time to paint. But it did not mean that he did not paint at all. After 1500, visitors to the duke’s palace remarked on various stages and versions of the Virgin and Child with St. Anne and the Madonna of the Yarnwinder, and these were not the only paintings they said the master’s brush touched. After his visit to Leonardo in Florence, Fra Pietro da Novellara wrote to Isabella d’Este that although he was not making paintings as such, “two of his assistants make copies, and from time to time he adds some touches to them.” Sixteen years later an aide of the cardinal of Aragon, Antonio de Beatis, wrote much the same thing when he visited Leonardo in France. Leonardo was no longer producing masterpieces himself, he wrote. “He can no longer color with such sweetness as he used to,” but “he is nonetheless able to do drawings and teach others,” and he had “trained up a Milanese pupil who works well.”
*1 The mountain that was, in Greek mythology, the home of the Muses, and frequented by Apollo and Dionysus.
*2 Quoted in Martin Kemp, Leonardo da Vinci: The Marvellous Works of Nature and Man, Oxford University Press, 2007, p. 153.
*3 Ibid.
*4 Either Leonardo sent his blueprints for this automaton to the French court and it was built there, or he built it in his studio and sent it to France, because he was not present when it was put into operation.
*5 The Russian Leonardist Vasily Zubov argued that “Leonardo asserted, with much greater persistence than his predecessors like Brunelleschi and Ghiberti, that the practical efforts of the technician and artist should be based on conscious generalizations, on general laws.”
*6 V. P. Zubov, Leonardo da Vinci, translated by David H. Kraus, Harvard, 1968, p. 111.
*7 “With this mill I will generate a breeze at any time during the summer,” wrote Leonardo. “And I will make water spring up fresh and bubbling…the mill will serve to create conduits of water through the house, and fountains in various places.”