Leonardo da Vinci

Apprenticeships

Leonardo’s artistic inclinations must have appeared early. When he was about 15, his father, who enjoyed a high reputation in the Florence community, apprenticed him to artist Andrea del Verrocchio. In Verrocchio’s renowned workshop Leonardo received a multifaceted training that included painting and sculpture as well as the technical-mechanical arts. He also worked in the next-door workshop of artist Antonio Pollaiuolo.

Leonardo’s remarkable talent, especially his keenness of observation and creative imagination, was already apparent in the angel he contributed to Verrocchio’s Baptism of Christ (c. 1470–75): Leonardo endowed the angel with natural movement, presented it with a relaxed demeanor, and gave it an enigmatic glance that acknowledges its surroundings while remaining inwardly directed. In Leonardo’s landscape segment in the same picture, he also found a new expression for what he called “nature experienced”: He reproduced the background forms in a hazy fashion as if through a veil of mist.

In 1472 Leonardo was accepted into the painters’ guild of Florence, reflecting the increasingly formalized artistic training of 15th-century Europe from apprenticeship to guild. He nonetheless remained in his teacher’s workshop for five more years, after which time he worked independently in Florence until 1481. There are a great many superb extant pen and pencil drawings from this period, including many technical sketches—for example, pumps, military weapons, mechanical apparatus—that offer evidence of Leonardo’s interest in and knowledge of technical matters even at the outset of his career.

Early independent works

Ginevra de’ Benci

Leonardo again resisted tradition in another early painting, the portrait of Ginevra de’ Benci (c. 1474/78). Inspired by the dynamism of the portraits done by his Northern contemporaries, Leonardo broke with the customary profile portrait and portrayed the young woman in a three-quarter pose. In the unfinished St. Jerome (c. 1482) Leonardo’s early interest in anatomy shows in the structural accuracy of the saint’s emaciated body, while his mastery of gesture and facial expression gives the figure an unrivaled articulation of transfigured sorrow.

Adoration of the Magi

The interplay of masterful technique and affective gesture is also the chief concern of Leonardo’s first large creation containing many figures, the unfinished Adoration of the Magi (c. 1482). Intended for the monastery of San Donato a Scopeto, the piece was also one of his first substantial commissions from the city of Florence. Although Leonardo abandoned the work before departing for Milan in 1482, the painting nonetheless affords rich insight into the master’s subtle methods. The various aspects of the scene are built up from the base with very delicate paper-thin layers of paint in sfumato (the smooth transition from light to shadow) relief. The main treatment of the Virgin and Child group and the secondary treatment of the surrounding groups are clearly set apart with a masterful sense of composition—the pyramid of the Virgin Mary and Magi is demarcated from the arc of the adoring followers. Yet thematically they are closely interconnected: The bearing and expression of the figures—most striking in the group of praying shepherds—depict many levels of profound amazement.

Artworks from the first Milanese period

As a master artist, Leonardo maintained an extensive workshop in Milan, employing apprentices and students. Among his pupils at this time were Giovanni Antonio Boltraffio, Ambrogio de Predis, Bernardino de’ Conti, Francesco Napoletano, Andrea Solari, Marco d’Oggiono, and Salai. The role of most of these associates is unclear, leading to the question of Leonardo’s so-called apocryphal works, on which the master collaborated with his assistants. Scholars have been unable to agree in their attributions of these works.

The Virgin of the Rocks

Historians do agree that Leonardo completed at least six paintings during the 17 years he spent in Milan. (According to contemporary sources, Leonardo was commissioned to create three more pictures, but these works have since disappeared or were never done.) The earliest of these is probably The Virgin of the Rocks, an altar painting for the church of San Francesco Grande, Milan, that he began about 1483. The work reveals Leonardo’s painting at its purest. It depicts the apocryphal legend of the meeting in the wilderness between the young John the Baptist and Jesus about the time of the Holy Family’s flight into Egypt.

The secret of The Virgin of the Rocks’s effect lies in Leonardo’s use of every means at his disposal to emphasize the sacred nature of the scene. Using sfumato to create subtle tonal transitions, he models the figures with heightened naturalism and bathes them in soft, radiant light. Their quiet, restrained attitudes lend the scene a meditative, solemn quality, while the meaningful gesture with which the angel (the only figure facing the viewer) points to John reflects his role as the intercessor between the Son of God and humanity. All this combines, in a patterned and formal way, to create a moving and highly expressive work of art.

The project, however, led to 10 years of litigation between the Confraternity of the Immaculate Conception, which commissioned it, and Leonardo. For uncertain reasons, this legal dispute led Leonardo to create another version of the work that he completed in 1508.

Milan portraits

Leonardo is also believed to have completed several portraits in Milan, including Portrait of a Musician (c. 1485), Lady with an Ermine (c. 1489), and Portrait of a Woman (1490–97; called La Belle Ferronnière). Each of the three portraits uses the three-quarter pose Leonardo had adopted for Ginevra de’ Benci, but they suggest some experimentation with creating movement. Lady with an Ermine is the most dynamic. The lady, thought to be Cecilia Gallerani, the mistress of Ludovico Sforza, Leonardo’s patron in Milan, sits facing the viewer’s left, but her head turns to the right, as do her eyes, seemingly directed toward something outside the frame. The movement suggests a subtle S-curve, which is echoed by the ermine’s body. The Musician, on the other hand, is perhaps the most static, with the sitter’s face, eyes, and body facing the same direction. Indeed, several scholars have doubted Leonardo’s authorship of this work because of the lack of movement. La Belle Ferronnière most closely resembles Leonardo’s later portrait, the famed Mona Lisa, with her body and head facing toward the viewer’s left and her eyes gazing toward the right.

Last Supper

Leonardo’s other paintings from this period were frescoes. He made the decorative ceiling painting (c. 1498) for the Sala delle Asse in Milan’s Castello Sforzesco, but more significantly, the wall painting Last Supper (1495–98), one of the most famous artworks in the world. The painting was commissioned for the refectory of the monastery of Santa Maria delle Grazie, connecting the sacred subject directly to the monks’ own communal dining. In its monumental simplicity, the composition of the scene is masterful; the power of its effect comes from the striking contrast in the attitudes of the 12 disciples as counterposed to Christ. Leonardo portrayed a moment of high tension when, surrounded by the Apostles as they share Passover, Jesus says, “One of you will betray me.” The Apostles—as human beings who do not understand what is about to occur—are agitated, whereas Christ alone, conscious of his divine mission, sits in lonely, transfigured serenity. Only one other being shares the secret knowledge: Judas, who is both part of and yet excluded from the movement of his companions. In this isolation he becomes the second lonely figure—the guilty one—of the company.

In the profound conception of his theme, in the perfect yet seemingly simple arrangement of the individuals, in the temperaments of the Apostles highlighted by gesture, facial expressions, and poses, in the drama and at the same time the sublimity of the treatment, Leonardo attained a height of expression that has remained a model of its kind. Countless painters in succeeding generations, among them great masters such as Peter Paul Rubens and Rembrandt, marveled at Leonardo’s composition and were influenced by it and by the painting’s narrative quality. The work also inspired some of Johann Wolfgang von Goethe’s finest pages of descriptive prose. It has become widely known through countless reproductions and prints, the most important being that produced by Raffaello Morghen in 1800. Thus, Last Supper has become part of humanity’s common heritage and remains today one of the world’s outstanding paintings.

Technical deficiencies in the execution of the work have not lessened its fame. Leonardo was uncertain about the technique he should use. He bypassed traditional fresco painting, which, because it is executed on fresh plaster, demands quick and uninterrupted painting, in favor of another technique he had developed: tempera on a base, which he mixed himself, on the stone wall. This procedure proved unsuccessful, inasmuch as the base soon began to loosen from the wall. Damage appeared by the beginning of the 16th century, and deterioration soon set in. By the middle of the century, the work was called a ruin. Later, inadequate attempts at restoration only aggravated the situation, and not until modern restoration techniques were applied after World War II was the process of decay halted. A major restoration campaign begun in 1980 and completed in 1999 restored the work to brilliance but also revealed that very little of the original paint remains.

Salvator Mundi

Historians in the 21st century believe that about the turn of the century Leonardo likely contributed to Salvator Mundi (c. 1500; “Savior of the World”), the painting that sold for a record-breaking $450.3 million at auction in 2017. Although the panel was marketed as a wholly Leonardo work, some scholars believe that the master painted just a few passages, such as the blessing hand and the tendrils of hair. Nonetheless, the large sum, which also overlooked the fact that the painting’s poor condition required extensive conservation, attested to Leonardo’s enduring celebrity and his powerful position in the art history canon centuries after his death.

Starting the notebooks

It was during his first years in Milan that Leonardo began the earliest of his notebooks. He would first make quick sketches of his observations on loose sheets or on tiny paper pads he kept in his belt and at various points in his career attempt to arrange the notes according to theme. During this period, his interest in two fields—the artistic and the scientific—developed and shaped his future work, building toward a kind of creative dualism that sparked his inventiveness in both fields. He gradually gave shape to four main themes that were to occupy him for the rest of his life: a treatise on painting, a treatise on architecture, a book on the elements of mechanics, and a broadly outlined work on human anatomy. His geophysical, botanical, hydrological, and aerological researches also began in this period and constitute parts of the “visible cosmology” that loomed before him as a distant goal. He scorned speculative book knowledge, favoring instead the irrefutable facts gained from experience—from saper vedere.

One special feature that makes Leonardo’s notes and sketches unusual is his use of mirror writing. Leonardo was left-handed, so mirror writing came easily and naturally to him—although it is uncertain why he chose to do so. While somewhat unusual, his script can be read clearly and without difficulty with the help of a mirror—as his contemporaries testified—and should not be looked on as a secret handwriting. But the fact that Leonardo used mirror writing throughout the notebooks, even in his copies drawn up with painstaking calligraphy, forces one to conclude that, although he constantly addressed an imaginary reader in his writings, he never felt the need to achieve easy communication by using conventional handwriting. His writings must be interpreted as preliminary stages of works destined for eventual publication that Leonardo never got around to completing. In a sentence in the margin of one of his late anatomy sketches, he implores his followers to see that his works are printed.

Another unusual feature in Leonardo’s writings is the relationship between word and picture in the notebooks. Leonardo strove passionately for a language that was clear yet expressive. The vividness and wealth of his vocabulary were the result of intense independent study and represented a significant contribution to the evolution of scientific prose in the Italian vernacular. Despite his articulateness, Leonardo gave absolute precedence to the illustration over the written word in his teaching method. Hence, in his notebooks, the drawing does not illustrate the text; rather, the text serves to explain the picture. In formulating his own principle of graphic representations—which he called dimostrazione (“demonstrations”)—Leonardo’s work was a precursor of modern scientific illustration.

Anatomical studies and drawings

It cannot be determined exactly when Leonardo began to perform dissections, but it might have been several years after he first moved to Milan, at the time a center of medical investigation. His study of anatomy, originally pursued for his training as an artist, had grown by the 1490s into an independent area of research. Leonardo’s fascination with anatomical studies reveals a prevailing artistic interest of the time. In his own treatise Della pittura (1435; “On Painting”), theorist Leon Battista Alberti urged painters to construct the human figure as it exists in nature, supported by the skeleton and musculature, and only then clothed in skin. Although the date of Leonardo’s initial involvement with anatomical study is not known, it is sound to speculate that his anatomical interest was sparked during his apprenticeship in Andrea del Verrocchio’s workshop, either in response to his master’s interest or to that of Verrocchio’s neighbor Pollaiuolo, who was renowned for his fascination with the workings of the human body.

As his sharp eye uncovered the structure of the human body, Leonardo became fascinated by the figura istrumentale dell’ omo (“man’s instrumental figure”), and he sought to comprehend its physical working as a creation of nature. Over the following two decades, he did practical work in anatomy on the dissection table in Milan, then at hospitals in Florence and Rome, and in Pavia, where he collaborated with the physician-anatomist Marcantonio della Torre. By his own count Leonardo dissected 30 corpses in his lifetime.

Leonardo’s early anatomical studies dealt chiefly with the skeleton and muscles; yet even at the outset, Leonardo combined anatomical with physiological research. From observing the static structure of the body, Leonardo proceeded to study the role of individual parts of the body in mechanical activity. This led him finally to the study of the internal organs; among them he probed most deeply into the brain, heart, and lungs as the “motors” of the senses and of life. His findings from these studies were recorded in the famous anatomical drawings, which are among the most significant achievements of Renaissance science. The drawings are based on a connection between natural and abstract representation; he represented parts of the body in transparent layers that afford an “insight” into the organ by using sections in perspective, reproducing muscles as “strings,” indicating hidden parts by dotted lines, and devising a hatching system. The genuine value of these dimostrazione lay in their ability to synthesize a multiplicity of individual experiences at the dissecting table and make the data immediately and accurately visible; as Leonardo proudly emphasized, these drawings were superior to descriptive words. The wealth of Leonardo’s anatomical studies that have survived forged the basic principles of modern scientific illustration. It is worth noting, however, that during his lifetime, Leonardo’s medical investigations remained private. He did not consider himself a professional in the field of anatomy, and he neither taught nor published his findings.

Vitruvian Man

Alongside his anatomical investigations, Leonardo explored the human body as a system of mathematical proportions. Working with the mathematician Luca Pacioli, Leonardo considered the proportional theories of Vitruvius, the 1st-century-bce Roman architect, as presented in his treatise De architectura (“On Architecture”). Imposing the principles of geometry on the configuration of the human body, Leonardo demonstrated that the ideal proportion of the human figure corresponds with the forms of the circle and the square. In his illustration of this theory, the so-called Vitruvian Man, Leonardo demonstrated that when a man places his feet firmly on the ground and stretches out his arms, he can be contained within the four lines of a square, but when in a spread-eagle position, he can be inscribed in a circle.

Leonardo envisaged the great picture chart of the human body he had produced through his anatomical drawings and Vitruvian Man as a cosmografia del minor mondo (“cosmography of the microcosm”). He believed the workings of the human body to be an analogy, in microcosm, for the workings of the universe. Leonardo wrote: “Man has been called by the ancients a lesser world, and indeed the name is well applied; because, as man is composed of earth, water, air, and fire…this body of the earth is similar.” He compared the human skeleton to rocks (“supports of the earth”) and the expansion of the lungs in breathing to the ebb and flow of the oceans.

Equestrian sculpture for Francesco Sforza

In addition to his anatomical studies, Leonardo also made plans and sketches for artworks in his notebooks, and it is thanks to these that historians can glean information on his lost or incomplete art projects. One of these incomplete projects was the bronze equestrian statue commissioned to honor Francesco Sforza, the father of Leonardo’s patron in Milan and the founder of the Sforza dynasty. The grandiose sculptural project seems to have been the real reason Leonardo was invited to Milan, and he spent 12 years—with interruptions—on this task. It was one of the two great sculptural projects of his career to which he devoted himself wholeheartedly but which were not realized.

The project yielded a clay model of the horse, which was put on public display in 1493 on the occasion of the marriage of Bianca Maria Sforza, the niece of Leonardo’s patron Duke Ludovico Sforza, to Emperor Maximilian. Preparations were made to cast the colossal figure, which was to be 16 feet (5 meters) high. But, because of the imminent danger of war, the metal, ready to be poured, was used to make cannons instead, causing the project to come to a halt. The fall of Ludovico about the turn of the century sealed the fate of this abortive undertaking: The ensuing war left the clay model a heap of ruins.

Drawings of the monument, however, do exist, and they reveal the greatness of Leonardo’s vision of sculpture. Exact studies of the anatomy, movement, and proportions of a live horse preceded the sketches; Leonardo even seems to have thought of writing a treatise on the horse. He pondered the merits of two positions for the animal—galloping or trotting—and decided in favor of the latter. His sketches, superior in the suppressed tension of horse and rider to the achievements of Donatello’s statue of Gattamelata and Verrocchio’s statue of Bartolomeo Colleoni, are among the most beautiful and significant examples of Leonardo’s art. Unquestionably—as ideas—they exerted a very strong influence on the development of equestrian statues in the 16th century.

The most impressive sketches were found in 1965 when two of Leonardo’s notebooks—the so-called Madrid Codices—were discovered in the National Library of Madrid. These notebooks reveal the sublimity but also the almost unreal boldness of his conception. Text and drawings both show Leonardo’s wide experience in the technique of bronze casting, but at the same time they reveal the almost utopian nature of the project. He wanted to cast the horse in a single piece, but the gigantic dimensions of the steed presented insurmountable technical problems. Indeed, Leonardo remained uncertain of the problem’s solution to the very end.

Artworks from the second Florentine period

In the Florence years between 1500 and 1506, Leonardo began three great works that confirmed and heightened his fame: The Virgin, the Child Jesus, and Saint Anne (1503–19), Mona Lisa (1503–19), and Battle of Anghiari (unfinished; begun 1503). Even before it was completed, The Virgin, the Child Jesus, and Saint Anne won the critical acclaim of the Florentines; the monumental three-dimensional quality of the group and the calculated effects of dynamism and tension in the composition made it a model that inspired classicists and Mannerists in equal measure.

Mona Lisa

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The Mona Lisa set the standard for all future portraits. The painting presents a woman revealed in the 21st century to likely have been Lisa del Giocondo, the wife of the Florentine merchant Francesco del Giocondo—hence, the alternative title to the work, La Gioconda. The picture presents a half-body portrait of the subject, with a distant landscape visible as a backdrop. Although utilizing a seemingly simple formula for portraiture, the expressive synthesis that Leonardo achieved between sitter and landscape has placed this work in the canon of the most popular and most analyzed paintings of all time.

Leonardo’s facility with sfumato gives the sitter a gently modeled form, while his knowledge of atmospheric perspective, in which far-off objects such as trees, rock formations, and bridges become softer and lighter, creates the illusion of a receding space. The sensuous curves of the woman’s hair and clothing are echoed in the undulating valleys and rivers behind her. The sense of overall harmony achieved in the painting—especially apparent in the sitter’s faint smile—reflects Leonardo’s idea of the cosmic link connecting humanity and nature, making this painting an enduring record of Leonardo’s vision and genius. The young Raphael sketched the work in progress, and it served as a model for his Portrait of Maddalena Doni.

(Read Britannica’s essay “Why Is the Mona Lisa So Famous?”)

Battle of Anghiari

Leonardo’s art of expression reached another high point in the unfinished Battle of Anghiari. The prized commission, a mural intended for the council hall in Florence’s Palazzo Vecchio, was designed to honor the 1440 victory over Milanese forces, effectively linking military triumph to the city’s civic identity. At 23 by 56 feet (7 by 17 meters), it was intended as a historical scene of monumental proportions and would have been twice as large as the Last Supper. For three years Leonardo worked on the Battle of Anghiari; like its intended complementary painting, Michelangelo’s Battle of Cascina, it ultimately remained unfinished. The preliminary drawings—many of which have been preserved—reveal Leonardo’s lofty conception of the “science of painting”; he put to artistic use the laws of equilibrium that he had probed in his studies of mechanics. The “center of gravity” in the work lies in the group of flags fought for by all the horsemen. For a moment the intense and expanding movement of the swirl of riders seems frozen. Leonardo’s studies in anatomy and physiology not only influenced his naturalistic representation of human and animal bodies but also his vivid articulation of extreme emotion, particularly when they are in a state of excitement. He studied and described extensively the baring of teeth and puffing of lips as signs of animal and human anger. On the painted canvas, rider and horse, their features distorted, are remarkably similar in expression.

The highly imaginative trappings of the painting take the event out of the sphere of the historical and put it into a timeless realm. The cartoon and the copies showing the main scene of the battle were for a long time influential to other artists; to quote the sculptor Benvenuto Cellini, the works became “the school of the world.” Its composition has influenced many painters: from Peter Paul Rubens in the 17th century, who made the most impressive copy of the scene from Leonardo’s now-lost cartoon, to Eugène Delacroix in the 19th century.

Art from the second Milanese period

During this second period in Milan, Leonardo gathered pupils around him. Of his older disciples, Bernardino de’ Conti and Salai were again in his studio; new students came, among them Cesare da Sesto, Giampetrino, Bernardino Luini, and the young nobleman Francesco Melzi, Leonardo’s most faithful friend and companion until the artist’s death. Leonardo, however, created very little as a painter. He returned to the Leda theme—which had been occupying him for a decade—and probably finished a standing version of Leda about 1513 (the work survives only through copies). This painting became a model of the figura serpentinata (“sinuous figure”)—that is, a figure built up from several intertwining views. It influenced classical artists such as Raphael, who drew it, but it had an equally strong effect on Mannerists such as Jacopo da Pontormo. The drawings he prepared—revealing examples of his late style—have a curious, enigmatic sensuality.

The Trivulzio monument

While in Milan, Leonardo received an important commission. Gian Giacomo Trivulzio had returned victoriously to Milan as marshal of the French army and as a bitter foe of Ludovico Sforza, Leonardo’s former patron. Trivulzio commissioned Leonardo to sculpt his tomb, which was to take the form of an equestrian statue and be placed in the mortuary chapel donated by Trivulzio to the church of San Nazaro Maggiore. After Leonardo spent years of preparatory work on the monument, for which a number of significant sketches have survived, the marshal himself gave up the plan in favor of a more modest one. This was the second aborted project Leonardo faced as a sculptor.

St. John the Baptist

Perhaps in Milan Leonardo began the painting St. John the Baptist (1508–19), which he completed in France. Leonardo radically used light and shade to achieve sculptural volume and atmosphere; John emerges from darkness into light and seems to emanate light and goodness. Moreover, in painting the saint’s enigmatic smile, he presented Christ’s forerunner as the herald of a mystic oracle. Leonardo’s was an art of expression that seemed to strive consciously to bring out the hidden ambiguity of the theme.

Visions of the End of the World and other late artworks

Leonardo did little painting while in France, though he frequently returned to the paintings that he considered unfinished and that he had been carrying with him for more than a decade. These included the Mona Lisa and The Virgin, the Child Jesus, and St. Anne. Otherwise he spent most of his time arranging and editing his scientific studies, his treatise on painting, and a few pages of his anatomy treatise.

Consummate drawings from this period, such as A Woman in a Landscape (c. 1517–18; also called the Pointing Lady), however, are testaments to his undiminished talent. The last manifestation of Leonardo’s art of expression was in his series of pictorial sketches, called Visions of the End of the World (c. 1517–18). There Leonardo’s power of imagination—born of reason and fantasy—attained its highest level. Leonardo suggested that the immaterial forces in the cosmos, invisible in themselves, appear in the material things they set in motion. What he had observed in the swirling of water and eddying of air, in the shape of a mountain boulder and in the growth of plants, now assumed gigantic shape in cloud formations and rainstorms. He depicted the framework of the world as splitting asunder, but even in its destruction there occurs—as the monstrously “beautiful” forms of the unleashed elements show—the self-same laws of order, harmony, and proportion that presided at the world’s creation. These rules govern the life and death of every created thing in nature. Without any precedent, these “visions” are the last and most original expressions of Leonardo’s art—an art in which his perception based on saper vedere seems to have come to fruition.

“On Painting”

After inheriting Leonardo’s vast manuscript legacy in 1519, it is believed that, sometime before 1542, Melzi extracted passages from them and organized them into the Trattato della pittura (“Treatise on Painting”) that is attributed to Leonardo. Only about a quarter of the sources for Melzi’s manuscript—known as the Codex Urbinas, in the Vatican Library—have been identified and located in the extant notebooks, and it is impossible to assess how closely Melzi’s presentation of the material reflected Leonardo’s specific intentions.

Abridged copies of Melzi’s manuscript appeared in Italy during the late 16th century, and in 1651 the first printed editions were published in French and Italian in Paris by Raffaelo du Fresne, with illustrations after drawings by Nicolas Poussin. The first complete edition of Melzi’s text did not appear until 1817, published in Rome. The two standard modern editions are those of Emil Ludwig (1882; in 3 vol. with German translation) and A. Philip McMahon (1956; in 2 vol., a facsimile of the Codex Urbinas with English translation).

Despite the uncertainties surrounding Melzi’s presentation of Leonardo’s ideas, the passages in Leonardo’s extant notebooks identified with the heading “On Painting” offer an indication of the treatise Leonardo had in mind. As was customary in treatises of the time, Leonardo planned to combine theoretical exposition with practical information, in this case offering practical career advice to other artists. But his primary concern in the treatise was to argue that painting is a science, raising its status as a discipline from the mechanical arts to the liberal arts. He roots his case in the function of the senses, asserting that “the eye deludes itself less than any of the other senses,” and thereby suggests that the direct observation inherent in creating a painting has a truthful, scientific quality.

Leon Battista Alberti and Piero della Francesca had already offered proof of the mathematical basis of painting in their analysis of the laws of perspective and proportion, thereby buttressing Leonardo’s claim of painting being a science. But his claims went much further: He believed that the painter, doubly endowed with subtle powers of perception and the complete ability to pictorialize them, was the person best qualified to achieve true knowledge, as he could closely observe and then carefully reproduce the world around him. Hence, Leonardo conceived the staggering plan of observing all objects in the visible world, recognizing their form and structure, and pictorially describing them exactly as they are.

Leonardo’s defense of painting as a science uses the form of the paragone (“comparison”), a disputation that advances the supremacy of painting over the other arts. Unlike poetry, he argues, painting presents its results as a “matter for the visual faculty,” giving “immediate satisfaction to human beings in no other way than the things produced by nature herself.” Leonardo also distinguishes between painting and sculpture, claiming that the manual labor involved in sculpting detracts from its intellectual aspects, and that the illusionistic challenge of painting (working in two rather than three dimensions) requires that the painter possess a better grasp of mathematical and optical principles than the sculptor.

Indeed, in the notebooks Leonardo explains that the 10 optical functions of the eye (“darkness, light, body and color, shape and location, distance and closeness, motion and rest”) are all essential components of painting. He addresses these functions through detailed discourses on perspective that include explanations of perspectival systems based on geometry, proportion, and the modulation of light and shade. He differentiates between types of perspective, including the conventional form based on a single vanishing point, the use of multiple vanishing points, and aerial perspective. In addition to these orthodox systems, he explores—via words and geometric and analytic drawings—the concepts of wide-angle vision, lateral recession, and atmospheric perspective, through which the blurring of clarity and progressive lightening of tone is used to create the illusion of deep spatial recession. He further offers practical advice—again through words and sketches—about how to paint optical effects such as light, shadow, distance, atmosphere, smoke, and water, as well as how to portray aspects of human anatomy, such as human proportion and facial expressions.

Architecture

Early in his career when applying for service in a letter to Ludovico Sforza, duke of Milan, Leonardo described himself as an experienced architect, military engineer, and hydraulic engineer; indeed, he was concerned with architectural matters all his life. But his effectiveness was essentially limited to the role of an adviser. Only once—in the competition for the cupola of the Milan Cathedral (1487–90)—did he actually consider personal participation, but he gave up this idea when the model he had submitted was returned to him. In other instances, his claim to being a practicing architect was based on sketches for representative secular buildings: for the palace of a Milanese nobleman (about 1490), for the villa of the French governor in Milan (1507–08), and for the Medici residence in Florence (1515). Finally, there was his big project for the palace and garden of Romorantin in France (1517–19). These projects were never taken up, but Leonardo’s pencil sketches clearly reveal his mastery of technical as well as artistic architectural problems; the view in perspective gives an idea of the magnificence of the site.

But what really characterizes and immortalized Leonardo’s architectural studies is their comprehensiveness; they range far afield and embrace every type of building problem of his time and even involve urban planning. Furthermore, there frequently appears evidence of Leonardo’s impulse to teach: He wanted to collect his writings on this theme in a theory of architecture. This treatise on architecture—the initial lines of which are in Codex B in the Institut de France in Paris, a model book of the types of sacred and profane buildings—was to deal with the entire field of architecture as well as with the theories of forms and construction and was to include such items as urbanism, sacred and profane buildings, and a compendium of important individual elements (for example, domes, steps, portals, and windows).

In the fullness and richness of their ideas, Leonardo’s architectural studies offer an unusually wide-ranging insight into the architectural achievements of his epoch. Like a seismograph, his observations sensitively register all themes and problems. For almost 20 years he was associated with Bramante at the court of Milan and again met him in Rome in 1513–14; he was closely associated with other distinguished architects, such as Francesco di Giorgio, Giuliano da Sangallo, Giovanni Antonio Amadeo, and Luca Fancelli. Thus, he was brought in closest touch with all of the most significant building undertakings of the time. Since Leonardo’s architectural drawings extend over his whole life, they span precisely that developmentally crucial period—from the 1480s to the second decade of the 16th century—in which the principles of the High Renaissance style were formulated and came to maturity. That this genetic process can be followed in the ideas of one of the greatest men of the period lends Leonardo’s studies their distinctive artistic value and their outstanding historical significance.

Mechanics and cosmology

According to Leonardo’s observations, the study of mechanics, with which he became quite familiar as an architect and engineer, also reflected the workings of nature. Throughout his life Leonardo was an inventive builder; he thoroughly understood the principles of mechanics of his time and contributed in many ways to advancing them. The two Madrid notebooks deal extensively with his theory of mechanics; the first was written in the 1490s, and the second was written between 1503 and 1505. Their importance lay less in their description of specific machines or work tools than in their use of demonstration models to explain the basic mechanical principles and functions employed in building machinery. As in his anatomical drawings, Leonardo developed definite principles of graphic representation—stylization, patterns, and diagrams—that offer a precise demonstration of the object in question.

Leonardo was also quite active as a military engineer, beginning with his stay in Milan. But no definitive examples of his work can be adduced. The Madrid notebooks revealed that, in 1504, probably sent by the Florentine governing council, he stood at the side of the lord of Piombino when the city’s fortifications system was repaired and suggested a detailed plan for overhauling it. His studies for large-scale canal projects in the Arno region and in Lombardy show that he was also an expert in hydraulic engineering.

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Leonardo was especially intrigued by problems of friction and resistance, and with each of the mechanical elements he presented—such as screw threads, gears, hydraulic jacks, swiveling devices, and transmission gears—drawings took precedence over the written word. Throughout his career he also was intrigued by the mechanical potential of motion. This led him to design a machine with a differential transmission, a moving fortress that resembles a modern tank, and a flying machine. His “helical airscrew” (c. 1487) almost seems a prototype for the modern helicopter, but, like the other vehicles Leonardo designed, it presented a singular problem: It lacked an adequate source of power to provide propulsion and lift.

Wherever Leonardo probed the phenomena of nature, he recognized the existence of primal mechanical forces that govern the shape and function of the universe. This is seen in his studies of the flight of birds, in which his youthful idea of the feasibility of a flying apparatus took shape and which led to exhaustive research into the element of air; in his studies of water, the vetturale della natura (“conveyor of nature”), in which he was as much concerned with the physical properties of water as with its laws of motion and currents; in his research on the laws of growth of plants and trees, as well as the geologic structure of earth and hill formations; and, finally, in his observation of air currents, which evoked the image of the flame of a candle or the picture of a wisp of cloud and smoke.

In his drawings based on the numerous experiments he undertook, Leonardo found a stylized form of representation that was uniquely his own, especially in his studies of whirlpools. He managed to break down a phenomenon into its component parts—the traces of water or eddies of the whirlpool—yet at the same time preserve the total picture, creating both an analytic and a synthetic vision.