The window into da Vinci’s creativity? His sketchbooks

The achievements of Leonardo da Vinci elevate him to the realm of genius. Gazing upon his creations, such as “The Last Supper” or the “Mona Lisa,” it is difficult to imagine the mortal man who created these eternal masterpieces. Reading about his lifelong devotion to medicine, science, and engineering can make him feel even more remote. Connecting to the man behind the genius can feel impossible.

Leafing through Leonardo’s journals helps bridge the gap. He left behind thousands of loose manuscript pages, a rich trove of writings and sketches. These works reveal not only his brilliance—his scientific thoughts and sublime sketches—but also his ordinary quirks, like his doodles in the margins or his unusual way of writing. 

The words are mirror-written, with the letters back to front and crossing the page from right to left. There have been many theories as to why Leonardo chose to write this way. It may have kept the material hidden from prying eyes, or it may have been a means by which the left-handed Leonardo avoided smudging his letters as he wrote.

A window into Leonardo’s exceptional mind, the manuscripts contain jottings on mathematics, philosophy, botany, and medicine. His sketches include beautiful flowers, extraordinary inventions, and some of Leonardo’s most famous images, such as the “Vitruvian Man” from his youth and a craggy-faced old man—perhaps a self-portrait—created circa 1516.

(What’s inside Leonardo da Vinci’s notebooks?)

Career sketches

Born in 1452 near the hilltop town of Vinci, Leonardo grew up the illegitimate son of a notary father and a peasant mother. Few details about his early life are known, but his artistic talents could not have gone unnoticed. His talent took him to many different cultural centers of Renaissance Europe. 

In his teens, Leonardo apprenticed with artist Andrea del Verrocchio in Florence and remained there for seven years. Around age 20, he began taking independent commissions and working on his own. In 1482 the 30-year-old artist moved to Milan to enter the service of Ludovico Sforza, ruler of the city.

Under the job title of ducal painter and engineer, Leonardo combined his brilliance in painting, design, construction, and inventing. He designed a monumental equestrian statue in bronze and in 1497 completed “The Last Supper” for the refectory of the city’s Santa Maria delle Grazie monastery.

Following the fall of Milan to French troops in 1499, Leonardo served as a military architect, engineer, and cartographer for the cardinal and warlord Cesare Borgia. After a brief return to Florence during which he painted the “Mona Lisa,” he went back to Milan, this time in the service of the French. His connections with the French monarchy would serve him well: After a stint in Rome, the aged genius accepted an invitation from the French king to live in France as a guest of the crown. He died there in 1519 at age 67.

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Books of genius

Much of Leonardo’s writings could have been lost, succumbing to fire, flood, or theft, but through luck, and the intervention of those who saw their worth, many of the manuscripts and diaries survived. After Leonardo died in 1519, his vast manuscript archive passed to his heir, Francesco Melzi. Melzi held on to some of this material and formed a volume now celebrated as Leonardo’s Treatise on Painting. The original manuscript of the treatise—the Codex Urbinas Latinus 1270—now resides in the Vatican Library.

Following Melzi’s death in the 1570s, the many thousands of loose pages filled with sketches, notes, and jottings were acquired by a Spanish collector, Pompeo Leoni. These manuscripts were dispersed throughout Europe, ending up in Spanish museums or in aristocratic and royal collections in England.

A swath of the manuscripts were donated by Milanese nobleman Galeazzo Arconati to the Biblioteca Ambrosiana, later to be purloined and taken to France by Napoleon Bonaparte as spoils of war in the late 1700s. A few volumes eventually returned to Milan, and some returned to Turin. All the surviving Leonardo notebooks today are preserved in the collections of libraries and museums across Europe. There is one exception: the Codex Leicester, which in 1994 was bought by software tycoon Bill Gates.

During these journeys, the manuscripts have been bound, rebound, or stitched together to make bigger volumes. Some notebooks still retain part of Leonardo’s original unitary character, such as the Codex Leicester and the Madrid I and Madrid II Codices, whose pages are partially numbered in Leonardo’s hand.

Early papers

Few examples of Leonardo’s earliest sketches and notes still exist, but the ones that survive reveal the thoughts and observations of the time. These loose sheets are from his first decade in Florence, starting in 1472. Sketched when he was 21, Leonardo’s first drawing is a view of the Arno, the river that runs through Florence. Dated August 5, 1473, the landscape demonstrates his full mastery of perspective. In the upper left corner, Leonardo’s notes flow across the page from right to left; this “backward” writing habit would continue throughout his life. 

Another drawing captures a current event from this time in Florence: a criminal’s execution. On a tiny piece of paper is the hanging of Bernardo Bandini Baroncelli, who participated in a 1478 assassination attempt on Lorenzo de’Medici. Toward the end of this period in Florence, Leonardo’s interest in human anatomy was expressed in perhaps his most iconic drawing: the “Vitruvian Man,” from 1487-90. 

In their desire to relate the human body to the wider workings of the cosmos, humanists like Leonardo seized on the architectural theories of the first-century B.C. Roman writer Vitruvius. His treatise, rediscovered in the early 1400s, established proportional rules for the human body. In this sketch, Leonardo tests them. A figure of a man with his arms outstretched is contained in a square. Superimposed on the figure is another drawing of the same man, but with his arms and legs akimbo and circumscribed by a circle. In the margins of the drawing is Leonardo’s distinctive handwriting, running from right to left.

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The Paris B Codex

Leonardo created what is now known as the Paris B Codex. This volume is the oldest of the 12 volumes seized by Napoleon Bonaparte in the late 1700s and deposited in the Library of the Institute of France in Paris. Leonardo had a lifelong fascination with flight, inspired by observations of birds. In 1505 he wrote an entire Codex on the Flight of Birds. Scholars estimate that he made 500 sketches and wrote as many as 35,000 words on the subject across his whole career. 

The Paris B Codex contains two of Leonardo’s most celebrated designs for flying machines. Many of his famous designs were ornithopters, aircraft that fly by flapping their wings like birds and bats. Another early inspiration was likely a sketch by 13th-century Italian artist Giotto. In it, Giotto illustrates the Greek myth of the inventor Daedalus and his son Icarus, who don mechanical wings and fly to escape captivity. In addition to the flying machines, the Paris B manuscript also has entries that embody the wide range of Leonardo’s curiosity. 

A good example is a page combining beautiful sketches of blooming violets alongside practical sketches for soldering lead roofs. Fascinated by everything, he could engineer inventions that touched the sky, as well as depict precise forms of the most delicate petals. Scholars have noted that the cross-hatching technique on the violets was also being developed by Leonardo in his great picture “The Virgin of the Rocks,” a work he completed in the mid-1480s.

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The Codex Atlanticus

Pompeo Leoni, the Spanish collector who acquired Leonardo’s manuscripts from Francesco Melzi, compiled a vast number of drawings by the Florentine artist. Known as the Codex Atlanticus, it is preserved today in the Biblioteca Ambrosiana of Milan. The codex is enormous and contains more than a thousand folios. 

The pages, arranged on an aesthetic rather than thematic basis, reflect Leonardo’s many different interests at all stages of his career. They contain geometry and algebra, musical instruments, machines, flying devices, civic engineering projects (such as diverting the course of the Arno River), mechanical plans, urban planning, and anatomical drawings. 

Of great interest are cryptic notes by Leonardo about his own life. On one folio there is the famous reference to Leonardo’s childhood memory of a red bird that flew above his cradle and opened his mouth with its tail. On folio 196, Leonardo succinctly confirms that he carried out part of his anatomical studies in the hospital of Santa Maria Nuova in Florence, evidently using dissection. 

Also noteworthy is the enigmatic fragment on folio 429, where he laconically wrote “li medici mi creorono edesstrussono,” which means “doctors (or the Medici) created and destroyed me.” The question of whether those doing the destroying were doctors or the Medici (Florence’s rulers) is unresolved, but it likely refers to the latter. The codex also contains an intriguing list of the books in Leonardo’s personal library. They covered subjects from literature and grammar to mathematics and religion—giving a fuller impression of the subjects and writings that filled the great inventor’s mind.

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The Codex Windsor

The Codex Windsor is a collection of 600 folios, originally bound by Pompeo Leoni but today unbound. Acquired by King Charles I in 1630, it is held in the Royal Library at Windsor Castle in England. The codex contains the most complete series of Leonardo’s anatomical drawings, compiled by Leoni from several notebooks. 

The drawings include studies of human joints—how the muscles, tendons, ligaments, and bones fit and move together. One folio shows a human fetus curled up inside the womb, one of history’s first such detailed depictions. 

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The Codex Windsor is also notable for containing a large part of the studies of horse anatomy that Leonardo carried out in preparation for the equestrian monument commissioned by Ludovico Sforza. In keeping with his multi-faceted interests, Leonardo did not learn about horse anatomy in isolation: He obsessively studied horses in different positions. He studied expressions and demeanor in both horses and humans. 

Comparing and contrasting the expressions of snorting fury in horses and a man, this sheet was drawn as research into Leonardo’s 1503 mural depicting the Battle of Anghiari, a Milanese victory from the century before. In an observation elsewhere on the defeated in battle, Leonardo had noted “the lips arched to show the upper teeth, and the teeth apart as if crying out in lamentation.” It is both a study of the extreme emotions of the spirit as well as the mechanics of anatomy: Leonardo demonstrates how the expressions of such feelings can be transmitted by the musculature of the face, structures that he shows in meticulously observed detail.

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The Codex Arundel

Preserved in the British Library in London, the Codex Arundel is a great compendium of reflections on geometry, the workings of mirrors, and a mechanical organ. On folio 24, Leonardo reproduced his design for a prototype of a diving suit: Two tubes—one for exhaling waste air, and the other for inhaling—lead to the surface where they are attached to a float. 

Never constructed, the suit was likely devised with some military function in mind: Leonardo was in Venice at the time, offering his engineering services to the authorities there. 

Elsewhere in the codex, folio 272 contains a striking marginal note: “On Wednesday, July 9, 1504, at 7 o’clock, Ser Piero da Vinci, the notary at Podestà Palace, my father, died. He was 80 years old and left ten sons and two daughters.” Scholars have wondered what this laconic note reveals about Leonardo’s feelings, and whether a certain indifference is expressed toward his father’s passing. Other personal notes that pepper the Codex Arundel elsewhere are more mundane, keeping track of the genius’s everyday expenses: “I gave Salai twenty-one braccia of cloth for making shirts … on the twentieth day of April 1503.”

The Codex Leicester

This small codex, made up of 18 pages folded in two, contains sketches made by Leonardo between 1508 and 1510. Unlike many of the other codices, this collection has a clear theme, and scholars are confident that it was Leonardo himself who put the drawings together in the surviving volume. 

Much of the manuscript is dedicated to the study of water, which, Leonardo theorizes, circulates through the Earth like blood in animals and sap in plants: “Water rises from the depths of the sea to the summit of the mountains, where it is poured out” through springs. It contains stunning drawings of the luminosity of the moon, expressing Leonardo’s belief that its surface was made of water that reflected sunlight.

The Codex was preserved by a different route than Melzi’s legacy. In the 16th century it was owned by the sculptor Guglielmo della Porta, a disciple of Michelangelo. His heirs sold it to the painter Giuseppe Ghezzi, and in 1719 it was sold to the future Earl of Leicester. In 1980 it was acquired by the American oil tycoon Armand Hammer, and in 1994 another American millionaire, Bill Gates, paid 30 million dollars for it at auction.

(Why Leonardo da Vinci’s brilliance endures, 500 years later.)

Leonardo’s process

Today, Leonardo da Vinci is principally remembered as an artist, but his journals reveal his deep well of talent. Leonardo’s engineering and innovation interests drove his prodigious production of jottings and notes, in keeping with his instincts as a Renaissance humanist to seek to understand every aspect of nature. For Leonardo, drawing was also part of this process. Sketching, recording, revising, and theorizing became as important as a finished product.

With his relentless mind, Leonardo experienced the world as few—if any—ever had before. His mind seemed always to run at full steam, obsessed with the beauty of nature and human beings but also with innovation, using the natural world as inspiration. His is the eye of curiosity, as Leonardo himself wrote in his Treatise on Painting: “The eye embraces the beauty of the whole world … and is the window of the human body.” Thanks to his manuscripts, 500 years after his death, people can still observe that restless eye in action.