In the winter of 1489, Leonardo da Vinci requested permission from the authorities in Florence to exhume human corpses for dissection. He was thirty-seven years old and had already produced some of the most technically accomplished paintings of the Italian Renaissance. What he wanted now was not aesthetic inspiration but anatomical knowledge, the precise mechanics of how a human face moves when it smiles, how muscles attach to bone, how the eye receives light and transmits it to the brain. Over the following decades, he would dissect more than thirty bodies, working through the night in the morgues of Florentine and Milanese hospitals, filling notebook after notebook with drawings of such accuracy and beauty that they would not be surpassed for centuries. He was not doing this to paint better, or not only. He was doing it because he could not encounter a question without following it to its source, and the source of almost every question, for Leonardo, led eventually to the human body, the most complex mechanism in a world that he understood entirely in terms of mechanism. The smile of the Mona Lisa and the diagrams of tendons and cartilage in his anatomical notebooks are products of the same investigation, conducted with the same instrument, in the same restless hand.
What does it mean to be called a universal genius? Few figures in history embody that title as completely as Leonardo da Vinci (1452–1519). Painter, sculptor, engineer, anatomist, and inventor, Leonardo was the restless mind at the heart of the Italian Renaissance, a figure who recognized no boundary between art and science and pursued both with an intensity that left his contemporaries awed and his patrons frequently exasperated by projects he began and rarely finished. His notebooks, filled with sketches of flying machines, studies of the human body, designs for weapons and water systems, and observations on geology, botany, and optics, testify to a vision so far ahead of its time that many of his ideas would not be realized for centuries. His paintings, from the Mona Lisa to The Last Supper, remain among the most recognizable and most enigmatic works in the world.
Illuminating Leonardo's life and genius requires not just historical knowledge but the ability to move fluently between disciplines, a task ideally suited to Martin Kemp, Emeritus Research Professor in the History of Art at Oxford University and one of the world's foremost authorities on Leonardo. Kemp has devoted decades to studying the interplay of art and science across history, and his work, whether in books, lectures, or exhibitions, has helped audiences see Leonardo not as a distant icon preserved behind museum glass, but as a living mind grappling with problems that have never ceased to be interesting.
In the conversation that follows, Kemp sheds light on the secrets of Leonardo's mastery, explaining how his art and science fed into one another, why his works continue to captivate across centuries, and what we can still learn from a curiosity so insatiable that it drove a man to spend his nights in hospital morgues in pursuit of the mechanics of a smile.
Charles Carlini: You were featured prominently in NOVA’s Mystery of a Masterpiece special, wherein you were called upon to investigate whether a painting obtained by Peter Silverman was truly painted by Leonardo da Vinci. What are some of the telltale clues that would indicate Leonardo’s handiwork in a given painting?
Martin Kemp: The first thing to say is that it's not a painting. It is a highly innovative portrait on vellum in inks and colored chalk. Technically, it is a drawing or illumination.
There is a complex series of interlocking clues, ranging from stylistic to scientific. We can, for instance, look at the handling of the pen (to indicate whether it's definitely drawn left-handed) and the handprint technique in the flesh tones. We can situate it within the context of Milanese court portraiture of women, identifying it as a likely portrait of Duke Ludovico Sforza's illegitimate daughter, Bianca. Scientific examinations have revealed characteristic aspects of Leonardo's creative process and shown the extent of the restoration, especially in parts discordant with Leonardo, such as her green dress. The carbon dating and what we know about the provenance effectively rule out a forgery.
CC: That work, La Bella Principessa, is the subject of your 2010 book of the same name. Has the painting’s status as a Leonardo piece generally been accepted, or is there still resistance? Have there been any recent developments in the case of La Bella Principessa?
MK: As we saw in the Nova program, after the book was published, a professor in Florida, Dr. Edward Wright, suggested that it came from a copy of the Sforziada (a eulogy of the Duke's father, Francesco). We went with National Geographic to the National Library in Warsaw to follow up on this hint and found that the sheet on which the portrait was made almost certainly comes from the book. Even the stitch holes matched. That particular deluxe copy of the Sforziada was made for Bianca's marriage to Galeazzo Sanseverino, commander of the Duke's forces. Within a few months, Bianca had died. The evidence has been fully published in an Italian edition by Mandragora. Those few scholars who opposed it have gone rather quiet - but art historians are an obstinate lot!
Pascal Cotte in Paris now has some excellent new evidence about the underdrawing, which we hope to publish at some point.
CC: You count among your research interests the relationship between science and art—a relationship that Leonardo explored very thoroughly. How did Leonardo’s understanding of anatomy and nature translate into his paintings? Was his interest in scientific illustration unusual or typical of painters of his time?
MK: His interest was not unique. A mastery of perspective and anatomy was (in theory at least) necessary for painters who wished to depict the human body and nature in keeping with visual appearance. Andrea del Verrocchio, his master, had a command of perspective and was a master of the anatomical portrayal of the human figure. Leonardo went much further. He insisted that every aspect of nature, as "invented" by the artist in the paintings that emerged from his imagination, should be remade in accordance with natural law. This covered every aspect of the optics of seeing, the nature of the human body (beyond surface anatomy), the body of the earth (as in the Mona Lisa), and "the motions of the mind."
CC: You served as the editor of Leonardo on Painting, a compilation of Leonardo’s notes on the act of painting. How did Leonardo view his chosen craft? What aspects of him do his private notes reveal?
MK: Leonardo regarded art as a scientia—as the product of a systematic body of knowledge. His point was precisely that it was not a craft but an intellectual pursuit, fit for a gentleman. The painter stood above even the poet as the re-maker of nature through fantasia (imagination). The texts we edited were drawn from many notebooks. Leonardo himself never produced a final version of his planned treatise on painting, and the one eventually assembled by his pupil, Francesco Melzi, only partially reflects his intentions. We did not intend to reconstruct Leonardo's treatise, which is impossible, but rather to produce something that respects his overall order and his way of thinking. It's aimed at the non-specialist—to give an insight into the incredibly demanding program he set the painter in re-making nature. The notes reveal his obsessions and a certain amount of unrealistic expectations (not only for others but also for himself). His agenda was ultimately too big for anyone to realize.
CC: Leonardo da Vinci stands among the pantheon of great Renaissance painters; the Mona Lisa (or La Gioconda) is one of the most famous paintings of all time. What aspects of Leonardo’s painting set him above the average painter? What sort of techniques did he pioneer?
MK: Leonardo's works contain a very special combination of deep knowledge, which infuses every aspect of his art, but at the same time, he used techniques of visual and emotional ambiguity to invite the viewer into his paintings. The ambiguities relate to his ideas about vision and the indefiniteness of seeing that he discussed in his later notebooks. The science and expression are different sides of the same coin. His actual painting techniques are of indescribable delicacy, even beyond the reach of his closest followers. He seems to create living surfaces. I have twice seen the Mona Lisa out of its frame. It is spine-tingling!
CC: Are there any other paintings that are currently being disputed as possible Leonardo works? Do you believe any of them might be authentic?
MK: There are too many for this interview. I get sent candidates weekly, often by obsessive owners. The Salvator Mundi, first exhibited in London last year, is still being debated, but I think that it's seeping into general acceptance. The two recent discoveries are the first for over a century.
CC: A great deal of Renaissance art deals with religious subject matter, and Leonardo is no exception: The Last Supper stands along with the Mona Lisa as one of his most famous and popular works. Did Christianity have a significant impact on Leonardo’s career? Was he particularly religious?
MK: In the wake of the dreaded Da Vinci Code, there has been something of an obsession with Leonardo as an active heretic. I get many messages claiming that there are hidden images in Leonardo's paintings, ranging from figures from Dante to demons to alligators. There is no primary evidence in favor of this.
Leonardo believed absolutely in the divine creator of the world, and his will confirms his orthodox beliefs. He was not greatly concerned with theology and believed that the truths of revelation differed from those of reason. His actual works are incredibly successful in evoking a spiritual presence - both within and beyond his paintings. As an atheist, I would be happy if Leonardo joined the club, but he absolutely isn't a member.
CC: We know that Leonardo began painting with his apprenticeship to Andrea del Verrocchio, and it was from Verrocchio that Leonardo picked up what would become his own painting style. From a critical standpoint, how did Leonardo’s style develop after his apprenticeship ended? What elements of Verrocchio’s influence can be seen in Leonardo’s pieces?
MK: Leonardo learned a great deal from Verrocchio's work as a sculptor and draftsman. He learned about the anatomical and proportional portrayal of the body, about motion in space and the motion of the viewpoint, about the behavior of hair and draperies. Verrocchio was involved in almost all artistic media and engaged in engineering. Leonardo learned the least from Verrocchio as a painter! The master's painting style is very elusive. Leonardo's early paintings, like the Annunciation and the Munich Madonna, can be considered as products of Verrocchio & Co, plc.
CC: Leonardo was notorious for leaving pieces unfinished, a fact that he himself lamented—his unfinished works include St. Jerome in the Wilderness and The Adoration of the Magi. Why did Leonardo struggle with finishing so many of his pieces? How are these unfinished works treated by collectors and critics today?
MK: He set such high demands for each painting that it was difficult to realize them. His contemporaries clearly valued his unfinished works even in his lifetime.
But he finished the world’s most famous painting, which is probably the world's second most famous painting, and the world's most famous drawing. Few of us can claim to have finished anything even remotely as successful as that!
CC: Much of Leonardo’s life is shrouded in mystery, so his life and works tend to attract a considerable amount of conspiracy theories. In your work as a Leonardo scholar, have you encountered many misrepresentations about him? Are there any prominent misconceptions about his life and career?
MK: He is very well documented for an artist of his time. There are lots of documents, early accounts, and, of course, thousands of pages of writing. His life is not "shrouded in mystery." The "mystery" has been manufactured by those who find the truth too prosaic to account for the wonderful creations. Mona Lisa was the wife of a silk merchant. Boring, but true. But the documentation does not seem to explain why it is an image with such magic. The explanation lies in Leonardo’s imagination and skill, not in some speculative mystery. The big post-Dan-Brown misconception is that Leonardo was secretly communicating heretical messages in code to us 500 years later. Why? There are no "codes" in Renaissance paintings. There are "allegories" and "symbols," but these are integral to the picture's appearance and period reading, not secrets hidden by some deceptive strategy of secrecy.
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