# Leonardo da Vinci: The Art of Looking Closely

100 Lives That Shaped the World · Episode 5

## Chapter 1: A Wall That Would Not Behave

In the refectory of Santa Maria delle Grazie in Milan, a great wall painting began to deteriorate within decades of its completion. Leonardo da Vinci had not used conventional wet-plaster fresco. He worked largely on a dry prepared wall with an experimental combination of materials that permitted effects closer to panel painting and more opportunity for revision. Scientific examination continues to refine the exact sequence of layers, so a simple recipe should not be stated as certain. Moisture, the wall preparation, later damage, repainting, and restoration all affected *The Last Supper*. Its early fragility introduces a central question about Leonardo: how did close investigation produce both extraordinary images and projects that remained unstable, unfinished, or unpublished?

This decaying wall serves as a monument to Leonardo's entire career, illustrating the profound risks of his experimental mind. His life was defined by an insatiable habit of looking closely at the natural world. To Leonardo, the act of drawing was not merely a way to produce a finished product, but a tool for investigation. He observed the swirl of water around an obstacle, the flight of birds, the growth of plants, and the internal structure of the human body, believing that all these phenomena were governed by the same natural laws. This relentless curiosity meant that his artistic projects were never separate from his scientific inquiries. Yet, this very unity of art and investigation carried a heavy cost. His desire to understand the underlying mechanics of everything he painted often led to material risks, like the unstable paint on the Milanese wall, or to projects that remained forever incomplete. Patrons often despaired of receiving their commissioned works, as Leonardo would abandon a panel to study the geometry of a leaf or the mechanics of a pulley.

Why did so much of his work remain unfinished, and why were thousands of pages of observations never published in the form he imagined? Leonardo was not a solitary genius working in a vacuum, but a man embedded in the collaborative workshop culture of Renaissance Italy. He worked with patrons, assistants, and fellow craftspeople, while his surviving notebooks range far beyond the immediate needs of commissions. Changing patrons, war, technical experiments, ambitious standards, and the ordinary difficulty of large projects all contributed to work being delayed, transformed, or abandoned. The notebooks, filled with mirror writing and diagrams, were working papers rather than a single secret book. Some were preparations for treatises that never reached print. This gap between public commissions and unfinished inquiry defines much of his legacy, leaving a small group of accepted paintings and a much larger, dispersed archive of questions, trials, and plans.

## Chapter 2: A Workshop in Florence

In the spring of 1452, Leonardo was born near the Tuscan hill town of Vinci. His father, Ser Piero, was a successful notary, and his mother, Caterina, was a local peasant. Because his parents were unmarried, Leonardo was born out of wedlock, a status carrying significant social consequences in fifteenth-century Italy. It barred him from attending university, entering his father's legal profession, or receiving the traditional classical education of the wealthy elite. Instead of learning Latin, Greek, and scholastic philosophy in a formal classroom, Leonardo attended a local *scuola d'abaco*, learning basic reading, writing, and the practical mathematics used in commerce. This limited formal schooling forced him to rely on direct observation and personal experience, establishing a lifelong habit of looking closely at the natural world. He would later proudly style himself an *omo sanza lettere*—an unlettered man—turning this social barrier into an empirical strength.

By the late 1460s, Leonardo moved to Florence, a thriving center of trade, finance, and artistic innovation under the Medici. His father secured him an apprenticeship in the workshop of Andrea del Verrocchio, one of the most versatile and respected masters in the city. Verrocchio’s workshop was not a quiet, solitary studio, but a bustling commercial enterprise where art was treated as a collaborative craft. Assistants and apprentices worked side by side, producing everything from large-scale bronze sculptures and painted altarpieces to decorative armor, metalwork, and elaborate festival banners.

In this environment, artistic education was physical and material. Renaissance workshop apprentices commonly learned to grind pigments, mix binders, prepare panels with gesso, transfer drawings, and assist with many stages of production. Verrocchio’s busy shop also handled painting, sculpture, metalwork, and engineering problems, giving Leonardo access to skills across materials. Drawing, or *disegno*, joined design with close observation and became central to Leonardo’s practice. Studies of drapery, light, faces, animals, and bodies show how patiently he trained hand and eye, although surviving sheets cannot reconstruct every lesson or task from his apprenticeship.

This rigorous training united artistic representation with physical investigation. To paint a muscle accurately, Leonardo had to understand how it functioned beneath the skin. To depict a landscape, he had to study the behavior of light, the properties of the earth, and the flow of water. The workshop taught him that art was not merely decorative, but a systematic way of analyzing the physical world.

By 1472, at approximately twenty years of age, Leonardo qualified as a master in the Guild of Saint Luke, the Florentine painters' guild. Although this milestone allowed him to open his own independent workshop, his close relationship with Verrocchio led him to remain in his master’s shop for several more years to continue collaborating. During this period, he contributed to Verrocchio’s paintings, such as *The Baptism of Christ*, adding delicate details and a revolutionary use of oil glazes that began to show his unique approach to light and shadow. This collaborative, hands-on foundation in Florence shaped his belief that true knowledge came from looking closely at nature, laying the groundwork for a career where art and science were entirely inseparable.

## Chapter 3: Learning to See

In the Florentine workshop, drawing was not merely a preliminary step for a painting; it was a rigorous, primary method of inquiry. For Leonardo, the metalpoint stylus, ink, and red chalk became tools to dissect the visible world. He realized that to paint a human hand, a flowing stream, or a draped fabric accurately, he had to understand the physical laws governing them. This habit of looking closely united his artistic output with a broader investigation of nature, establishing a lifelong practice where art and science were entirely inseparable.

To master representation, he turned to geometry and the physics of light. He studied how light rays strike a curved surface, creating delicate gradations of shadow, and how reflection alters color. Linear perspective, a mathematical system developed by Florentine predecessors, allowed him to construct three-dimensional space on a flat panel. Yet, Leonardo observed that human vision does not see the world in sharp, geometric lines. He noticed that air has density, which softens the edges of distant objects and shifts their color toward blue—an observation that led to his development of atmospheric perspective.

This understanding of light and air birthed his signature technique, sfumato, a word derived from the Italian for smoke. Instead of defining forms with hard, artificial outlines, he blended dark and light tones so subtly that the transitions became imperceptible, mimicking the way shadows actually fall across a human face.

His pursuit of realism also demanded an understanding of what lay beneath the skin. To depict a body in motion, he studied the mechanics of joints, tendons, and muscles, comparing human limbs to mechanical levers. He observed how a shoulder shifts when an arm is raised, or how a neck muscle tenses when a head turns. This was an attempt to capture the internal impulses of the mind through external physical movement, translating human emotion into physical action.

These developing principles are visible in his earliest surviving collaborative works. In Andrea del Verrocchio’s workshop, master and assistants routinely shared the labor on a single commission, operating as a cohesive team where skills were passed from hand to hand. In a baptism scene painted around the mid-1470s, modern technical analysis confirms that Leonardo painted one of the angels and portions of the landscape. His brushwork, utilizing fluid oil glazes rather than the traditional egg tempera favored by his master, created a softer, more lifelike texture. His early independent work, such as an annunciation scene, further demonstrates this transition, balancing rigorous perspective with delicate botanical details that reveal his constant observation of living plants.

This method created a practical tension. A painting could become a problem of optics, anatomy, geometry, material, and expression all at once. Leonardo filled sheets with diagrams, optical studies, and anatomical sketches, but the record does not let historians reduce every unfinished commission to a single personality trait. Technical failure, changing patrons, political disruption, expanding research, and revision all mattered. The notebooks preserve the investigation in unusual detail even where a public work was delayed, altered, lost, or never completed.

## Chapter 4: Offering Every Skill to Milan

In the early 1480s, Leonardo left Florence for Milan, seeking the patronage of Ludovico Sforza, known by the epithet il Moro. A surviving letter associated with Leonardo presents a long list of possible military-engineering services, from bridges and fortifications to weapons, before briefly turning to painting and sculpture. Whether every proposal was original, practical, or ever tested is a different question. The document shows how an ambitious artist could address a court whose needs included defense, spectacle, construction, and prestige.

Once established in the Milanese court, Leonardo’s daily responsibilities often differed from his grand military proposals. Instead of building war machines, he became a master of courtly spectacle. He designed elaborate stage machinery, moving scenery, and fantastical costumes for ducal weddings and state festivals. One celebrated production featured a rotating dome representing the heavens, complete with actors dressed as planets. Through these temporary creations, Leonardo applied his deep study of geometry, mechanics, and optics. To his observant eye, the mechanics of a theatrical pulley and the physics of a defensive wall were parts of the same unified inquiry into how the physical world operated.

This close observation of physical forces filled his notebooks with drawings of weaponry, from multi-barreled firearms to giant crossbows. However, a significant gap existed between these paper proposals and built devices. Many of his military designs were conceptual exercises rather than practical blueprints. The metallurgical technology of the fifteenth century could not support the complex gear systems or the immense weight of his proposed vehicles. Furthermore, Sforza’s treasury prioritized immediate, conventional defenses over experimental technology. Leonardo’s military career in Milan remained largely one of advice, mapping, and conceptual drawing rather than active battlefield construction.

One of Leonardo's largest Milanese projects illustrates how ambition met political instability. Sforza commissioned an equestrian monument honoring his father. Leonardo studied horses, produced many drawings, and completed a full-scale clay model, but the bronze version was never cast. Metal reserved for the project was redirected as war threatened Milan. Later accounts describe occupying soldiers damaging the model. The surviving evidence establishes years of preparation and an unfinished monument, while some vivid details of its reception and destruction come through later storytelling.

Preparation followed by loss or abandonment marked several projects from Leonardo's Milanese years. His drawings connect the anatomy of a horse, the trajectory of a projectile, and the movement of stage machinery. Some designs were impractical, some responded to machines already known, and others remained exploratory sketches rather than construction plans. Funding, material limits, changing commissions, and political instability also shaped what could be completed. The notebooks matter because they preserve the process of looking and testing, not because every page contains an invention waiting for a later age.

## Chapter 5: Painting a Room Full of Reactions

In the dining hall of Santa Maria delle Grazie, Leonardo organized *The Last Supper* around a wave of gesture and response. The twelve companions form four groups, while perspective directs attention toward the central figure. Surviving studies and the finished composition show sustained attention to hands, faces, posture, and the geometry of the room. Later anecdotes describe Leonardo searching Milan for expressive models, but those stories should not be treated as a diary of his working days. The stronger evidence lies in the painting, preparatory drawings, documents, and early copies.

Traditional fresco required an artist to work in sections on wet plaster, limiting later adjustment. Leonardo instead painted *The Last Supper* largely on a dry prepared wall with an experimental mixture of materials. Scientific study continues to refine the exact sequence and composition of those layers. The method allowed effects closer to panel painting, but it bonded poorly in the refectory’s difficult environment. Deterioration began early, and later damage, repainting, environmental change, and restoration further altered what viewers see today.

Leonardo did not maintain a major court project in isolation. Assistants and workshop labor supported preparation, materials, drawings, and related copies, although scholars cannot assign every part of the surviving wall to a named hand with confidence. The broader workshop network matters: large Renaissance commissions depended on organized labor even when the master directed the design and painted crucial passages.

As the paint deteriorated, the work suffered centuries of neglect and well-meaning but destructive interventions. Early restorers, lacking modern chemical knowledge, painted over Leonardo's original brushstrokes with heavy, inaccurate pigments, distorting the subtle expressions he had carefully studied. The room was later used as a stable by invading troops, and during the Second World War, an aerial bomb destroyed the refectory's roof, leaving the protected wall exposed to the elements. It was not until a major, decades-long restoration project ending in the late twentieth century that conservators carefully removed centuries of overpainting. Using microscopic analysis, they revealed the surviving fragments of Leonardo's original work.

The fragile state of this masterpiece highlights the central paradox of Leonardo's career. His habit of looking closely and investigating materials pushed him to reject proven artistic formulas in favor of risky experiments. This restless drive to unite scientific observation with art often resulted in works that were either left unfinished or destined for rapid decay, leaving his greatest achievements as brilliant, vulnerable testaments to his curiosity.

## Chapter 6: Bodies, Water, Wings, and Machines

On the paper pages of Leonardo’s notebooks, different fields of study do not sit in isolation. A single sheet might display the curve of a human thigh muscle alongside the swirling currents of a river, the feathers of a bird’s wing, and the interlocking teeth of a wooden gear. For Leonardo, these subjects were not separate disciplines but interconnected parts of a single, visible world. His habit of looking closely united his artistic practice and his scientific inquiry, turning drawing into his primary tool for investigation. By recording the world with his pen, he sought to uncover the underlying rules that governed all of nature.

Leonardo participated in dissections of human bodies and animals, at times working where physicians could support access and interpretation. He recorded bones, muscles, organs, and movement from multiple views, using cross-sections, layered studies, and visual comparisons. These methods made complex structures unusually legible, although some drawings also retained inherited errors or uncertain conclusions. Notes indicate plans for an anatomical treatise, but no complete publication appeared in his lifetime, limiting the contemporary circulation of the studies.

This anatomical work was constantly informed by his study of other natural phenomena. Leonardo operated through analogies, finding patterns that repeated across different scales of existence. He compared the circulation of blood in human veins to the movement of water through the valleys of the earth, suggesting that the same physical laws governed both the microcosm of the body and the macrocosm of the world. He spent hours watching water flow past obstacles, sketching the tight spirals of turbulent eddies. He even compared these liquid vortices to the curls of human hair, using his draftsmanship to map the physics of fluid motion.

The air was another fluid medium that captured his attention. For decades, Leonardo studied the flight of birds, analyzing how they used their wings to balance, steer, and catch the wind. His early designs for flying machines attempted to mimic this flapping motion, relying on complicated systems of pulleys and levers powered by human muscles. Eventually, his close observation of birds led him to realize that human strength was insufficient for flapping flight, prompting him to study gliding instead.

Modern viewers must distinguish among different kinds of notebook drawings. Some relate to practical tools, waterways, fortifications, or theatrical machinery. Others examine geometry, friction, weight, or possible mechanisms. Famous flying devices and military engines are drawings, not proof of completed machines. In many cases historians cannot know whether a page records a commission, an adaptation of an older idea, a proposal, a test, or speculation. The notebooks are evidence of inquiry, but they are not a catalogue of modern inventions built centuries early.

Leonardo’s notes circulated far less widely than a printed or completed manuscript would have done. His left-handed mirror writing is often explained as a practical way to avoid dragging the hand through wet ink, although it may have had other conveniences. It was not a secure code. Some ideas were shared through workshops, patrons, collaborators, and drawings, while many remained in working papers that were later dispersed. Their limited publication reduced their direct influence on contemporary scholarly debate, even though they now provide exceptional evidence of his process.

## Chapter 7: War Changes the Map

In the autumn of 1499, the French army invaded Milan, forcing Ludovico Sforza into exile and shattering the stable court life Leonardo had enjoyed for nearly two decades. The French soldiers used his monumental clay model for the Sforza horse monument for target practice, destroying years of work. Suddenly without a primary patron, Leonardo became a traveler, seeking new opportunities across northern Italy. He visited Mantua, where he drew a portrait of Isabella d’Este, and Venice, where he advised the senate on coastal defenses against naval attacks.

By 1502, Leonardo’s search for patronage led him into the service of Cesare Borgia, the ambitious and ruthless commander who was conquering territories in central Italy. Appointed as Borgia’s general architect and engineer, Leonardo traveled through the Romagna region. Here, his habit of looking closely united artistic observation with practical military utility. Instead of drawing the traditional, pictorial views of towns common at the time, Leonardo created highly accurate, flat, top-down maps. For the town of Imola, he walked the streets with a magnetic compass and measured distances to construct an ichnographic map. This innovative visual tool allowed Borgia to see the defensive layout of the city at a single glance, demonstrating how geometry and artistic draftsmanship could serve strategic planning.

This period highlighted a profound ethical tension in Leonardo's life. In his notebooks, he described war in deeply critical terms, calling it a brutal and animalistic madness, yet he spent months designing fortifications, calculating trajectories, and mapping territories for one of the era's most violent warlords. His close observation of physical reality was not always neutral; it was often funded by those who sought power through force.

Leonardo returned to Florence in 1503, where the republican government offered him a prestigious commission: a massive wall painting of the Battle of Anghiari for the council hall of the Palazzo Vecchio. The project placed him in direct, tense competition with the younger sculptor Michelangelo, who was commissioned to paint a companion battle scene on the opposite wall. Leonardo threw himself into studying the anatomy of horses and the expressions of men in combat, seeking to capture the chaotic energy of war.

However, the project soon stalled. Seeking to avoid the rapid drying of traditional fresco, Leonardo experimented with an oil-and-wax mixture on the plaster wall. To dry the heavy layers of paint, he set up large charcoal braziers, but the heat was uneven. The paint began to run and melt down the wall, ruining the upper portions of the composition. Frustrated by this technical failure and distracted by new engineering projects, including a plan to divert the Arno River to secure Florentine access to the sea, Leonardo abandoned the mural.

The Battle of Anghiari remained unfinished, known today only through preparatory sketches and later copies by other artists. This outcome reflected a recurring pattern: Leonardo's relentless desire to experiment with materials and his tendency to prioritize the intellectual investigation of a subject over its physical completion often left his grandest projects as fragments. His close looking produced brilliant insights, but the practical demands of politics, war, and unstable materials frequently intervened.

## Chapter 8: The Painting He Kept

In the early sixteenth century, Leonardo began the portrait now called the *Mona Lisa*. Evidence strongly supports identifying the sitter as Lisa Gherardini, wife of the Florentine merchant Francesco del Giocondo, although aspects of the commission and its delivery remain uncertain. The panel was still associated with Leonardo late in his life and entered the French royal collection after his death. Technical examination shows revisions made during its development, but the surviving record cannot trace every journey of the painting or prove a single private reason he continued working on it.

The portrait became a living laboratory for Leonardo’s studies of light, optics, and human anatomy. Rather than applying paint in flat, distinct areas, he used his signature sfumato technique, building up dozens of microscopic, translucent glazes of oil paint over many years. This painstaking method mimicked how light actually behaves in the physical world, scattering softly over curved surfaces rather than ending at sharp outlines. His notebooks from this period are filled with diagrams of light hitting spheres and detailed dissections of the human face. He mapped the tiny muscles that move the lips, seeking to understand how a smile begins before it is even fully visible. The landscape behind the figure, with its winding rivers and crumbling crags, reflected his geological studies of water erosion and the deep history of the earth. For Leonardo, the portrait was not just a likeness; it was an investigation into how nature itself is structured.

Repeated revision fits a broader pattern in Leonardo’s career, from unfinished altarpieces to unrealized monuments. Later writers explained this through perfectionism or an unstable temperament, while modern admirers sometimes turn incompletion into proof of genius. Neither formula is enough. Documents, drawings, and objects instead point to changing commissions, technical risk, war, patronage, research, and a willingness to revise. They show process, but not the precise moment when Leonardo lost interest or decided that an intellectual problem was solved.

Patrons, contracts, and workshops imposed schedules, but the surviving evidence does not reduce every delay to Leonardo refusing to rush. The portrait’s soft transitions, layered landscape, and carefully modeled face do demonstrate long engagement with vision, atmosphere, and expression. Its importance lies in what can be examined on the panel and in its documented reception, not in an invented lifelong conversation between artist and sitter.

## Chapter 9: Companions, Rivals, and the Lone-Genius Myth

The popular image of Leonardo da Vinci often depicts a solitary figure working in absolute isolation. Yet, historical records reveal a man deeply embedded in a network of assistants, pupils, and rivals. His daily life was defined by the collaborative Renaissance workshop, or *bottega*, where art was a collective labor. In these environments, master artists functioned as educators and managers, overseeing projects where apprentices ground pigments, prepared panels, and painted minor background details under close supervision.

Among those who shared his daily routine, two figures stand out. Gian Giacomo Caprotti, nicknamed Salai, entered Leonardo’s household as a young boy in 1490. Despite a reputation for mischief documented in Leonardo’s notebooks, Salai remained a companion for three decades, serving as a model and assistant. Years later, Francesco Melzi, a young nobleman from Milan, joined the household. Melzi became a devoted pupil, organizing Leonardo’s chaotic manuscripts and acting as a trusted administrator. Upon Leonardo's death, Melzi inherited his writings, compiling them into the *Treatise on Painting* to preserve his master's legacy.

This close circle has invited speculation about Leonardo’s intimate life. Legal archives record an anonymous 1476 accusation of prohibited sexual conduct involving Leonardo and several other young men; the case was dismissed without a conviction. Salai and Melzi later occupied important places in his household and work, but surviving documents do not establish the private character of those relationships. Modern labels cannot be applied with certainty to fragmentary Renaissance evidence. A responsible biography can acknowledge both the record and its limits without turning uncertainty into either scandal or erasure.

Leonardo’s left-handed mirror writing has often been treated as evidence of secrecy. A simpler explanation is practical: writing from right to left can keep a left hand from moving across fresh ink. The habit also made casual reading less immediate, but it was not encryption, and ordinary left-to-right passages survive. Collections now called codices were assembled from working sheets with different purposes. They record private notes, calculations, copied information, drafts, and plans for wider projects rather than one hidden diary.

While Leonardo fostered cooperation within his own workshop, his relationship with other artists could be fraught. His most famous rivalry was with the younger sculptor and painter Michelangelo Buonarroti. In the early sixteenth century, the Florentine government commissioned both men to paint massive battle scenes on opposing walls of the grand council chamber in the Palazzo Vecchio. This direct competition highlighted their profound differences. Michelangelo, intense and focused on the heroic human form, clashed with the older, more polished Leonardo, who viewed painting as a science of light, shadow, and natural philosophy.

This rivalry underscored a broader tension in Leonardo’s career. His insistence on understanding the underlying mechanics of everything he painted meant that his preparatory work was incredibly vast. He could not simply paint a horse; he had to study its musculature and the physics of its movement, as seen in his aborted plans for the colossal Sforza monument. This exhaustive process of investigation often delayed his commissions, leading to unfinished projects like the *Adoration of the Magi*. For Leonardo, the act of looking closely and understanding the world was often more satisfying than the final physical product, a trait that puzzled his contemporaries but defined his unique legacy.

## Chapter 10: Pages Scattered Across Europe

In the autumn of 1516, Leonardo crossed the Alps to enter the service of King Francis I of France. Settling at the manor of Clos Lucé near the royal residence in Amboise, he carried with him his most cherished possessions: several unfinished paintings, including the portrait now known as the Mona Lisa, and dozens of leather-bound notebooks. In France, he received a generous pension as the premier painter, engineer, and architect to the king. Rather than producing major new paintings, he spent his final years organizing pageants, designing a grand royal palace and canal system at Romorantin, and organizing his scientific papers. He died at Clos Lucé on May 2, 1519, at the age of sixty-seven.

In his will, Leonardo bequeathed his notebooks, drawings, and anatomical studies to his loyal pupil and companion, Francesco Melzi. Melzi preserved these papers with great care at his family villa near Milan, but after his death around 1570, the collection suffered a chaotic fate. Heirs and dealers sold, divided, and neglected the manuscripts. Pages were bound into arbitrary volumes, while others vanished entirely. Over the centuries, these scattered sheets found their way into royal collections, private libraries, and museums across Europe, leaving a fragmented puzzle for future generations to piece together.

This fragmentation fueled a powerful myth. Separated from the collaborative workshop culture of the Renaissance, the isolated sketches of gears, wings, and weapons were often interpreted as the work of a solitary prophet who miraculously anticipated modern technology. Yet, historical context reveals that Leonardo was a man of his time, building upon existing medieval and Renaissance engineering traditions, even if his visual recording of these ideas was uniquely brilliant.

Leonardo’s work shows how looking closely could unite art and investigation. His pages connect faces with structures beneath the skin, movement with anatomy, machines with friction, and water with patterns of flow. Modern categories of art and science do not map neatly onto his world, and he did not erase every distinction among crafts or kinds of knowledge. What joins the work is repeated movement between observation, drawing, comparison, geometry, and material experiment.

There is no single answer to why so much remained unfinished or unpublished. Curiosity and revision mattered, but so did failed materials, interrupted patronage, political upheaval, ambitious scale, collaboration, and the gap between notes and a publishable treatise. Leonardo planned wider works on subjects including painting, water, and anatomy, yet the surviving sheets never became the complete public system he imagined. His legacy therefore rests both on finished objects and on an unusually visible process of seeing, testing, revising, and leaving questions open.