Human Journey

LEONARDO’S BRIDGE: Part 1. “The Master of all Trades”

Leonardo (1452-1519) created no more than 17 paintings during his lifetime. This part-time artist, who created the two most famous paintings in the history of art, was a consummate scientist-engineer, imbuing his art with science, and his science with art.

Portrait of Leonardo by his pupil Francesco Melzi (c. 1510).

Although he had virtually no formal education, he possessed relentless curiosity, which in combination with his extraordinary skills of observation, defined his unique modus operandi. His Codices, notebooks reminiscent of modern lab books, exude an almost divine quality. First, the drawings are far more beautiful than any ordinary scientist could have created; second, they show the depth and breadth of his understanding; and third, they reveal that he was routinely making discoveries centuries before they would be rediscovered. Five hundred years ago he designed machines to enable a man to walk on water, or to walk around breathing under water; siege engines to wage war, and machines to defend against attackers; portable bridges; machines for human flight; topographic maps; devices to measure humidity and wind speed… and machines that could grind mirrors to focus rays of light. Most likely he made a refracting astronomical telescope 100 years before Galileo, and a reflecting telescope 170 years before Isaac Newton reinvented it. (Among the blogs in National Geographic NewsWatch, please see the 4th in the series, ‘Brief History of the Astronomical Telescope: <a href=”“> A Brief History of the Astronomical Telescope </a>).

The design of a robotic cart. Notice the negative slope Leonardo has employed in the shading.

The drawing for a machine that had long been thought to be the blueprint of a ‘spring-driven cart’ was recently identified as a design in robotics. Among all the areas of science and technology in which he delved, it was in anatomical studies that he excelled. He produced drawings that have never been equaled in quality.

History’s Most Famous Left-Hander

Leonardo, in writing his thoughts in his notebooks, employed “mirror script,” writing backwards from right-to-left. To read his notes, one has to reflect them in a mirror, or hold up the reverse side against a strong light source. A simple rule of thumb that all sketch artists know instinctively is the direction of shading: a right-hander shades by creating parallel lines with positive slope (bottom left to top right); a left-hander creates parallel lines with negative slope (bottom right to top left, notice the direction of shading in the robotic car). Leonardo was left-handed, and he simply did not want to smudge the freshly laid down ink with the heel of his hand, nor to stab the paper in pushing his quill from left-to-right. He found it much faster to write backwards.

The English translation of a statement by Leonardo (using the Da Vinci Font), as he would have written it from right-to-left. It reads, “Nature, being inconstant and taking pleasure in creating…” [Note to the reader: Continue reading the statement, if you can. In somewhat ambiguous terminology, Leonardo appears to be prefiguring Darwin’s Theory of Evolution.””
Leonardo’s Curriculum Vita. In a 1482 letter intended for Ludovico Sforza, Leonardo opens with, “Most Illustrious Lord, Having now sufficiently considered the specimens of all those who proclaim themselves skilled contrivers of instruments of war, and that the invention and operation of the said instruments are nothing different from those in common use: I shall endeavor, without prejudice to any one else, to explain myself to your Excellency, showing your Lordship my secret… He concludes with “I also paint.”

He could, however, write in the conventional manner, from left-to-right. In applying for a job as a military engineer in 1482, he wrote to Ludovico Sforza, the strongman of Milan in the normal direction. The 900-word letter, his CV, identifies eleven types of inventions he has produced, or that he can produce (he changes tense). He describes portable bridges, armed carts designed to deflect light artillery (the tank)… and concludes with “…also I can do in painting whatever needs to be done.” Leonardo claims he can also paint!

In 1499 the French invaded Milan, and took Leonardo’s patron Duke Sforza prisoner. Leonardo, out of a job, took his assistant Salai and mathematician friend Luca Paccioli, and abandoned Milan. Heading east, the small party made its way to Venice. It was there in 1500, it is believed, Leonardo first came into contact with the merchants, trading partners of the Ottoman Turks, and where he first began to ruminate about a job in the Ottoman Court. This time he wrote a letter from right-to-left, in the convention of ‘0ld Turkish’ script (Whether he personally wrote it or hired a Turkish scribe to write it, we shall never know. There is no right- or left-handed shading in the letter, as there is in the drawings.)

Next: Part II. The letter to the Sultan

A little known project even among Leonardisti (scholars and fans of Leonardo) concerns Leonardo’s attempt to secure employment as a military engineer at the Ottoman Court. In the next installment in this series, we discuss a 510-year old letter (discovered only 60 years ago) proposing the construction of a bridge over Istanbul’s Golden Horn.


Bulent Atalay, a scientist, artist and author, has been described by NPR, PBS and the Washington Post as a “Modern Renaissance Man.” He is the author of two successful books on the intersection of art, science and mathematics, with Leonardo, the pre-eminent Renaissance man, serving as the foil. His best selling book, "Math and the Mona Lisa," (Smithsonian Books, 2004) has appeared in 13 languages. Professor Atalay's academic background is in theoretical physics. He travels around the world lecturing at academic institutions and on cruise ships on the "A-subjects," art, archaeology, astrophysics, atomic physics and Ataturk, confessing that he knows much less about the "B-subjects," business, banking, biology and botany... He is the President of the Ataturk Society of America (ASA), dedicated to promoting Ataturk's ideals of science and reason over dogma and superstition, of a secular state with full equality of genders. For more details click on Bulent Atalay
  • B Jones

    What a fascinating article! I look forward to reading Part II: Leonardo’s letter to the Sultan.

  • rauf sarper

    I never realized how long it took for the discovery of this letter.
    The details you presented so far are remarkable. I am looking forward to the next installments.
    Thanks for sharing.

  • Sergheii

    Leonardo is a legendary man, but how long it take researchers to discover all his secrets and discoveries? I was in Milan,in the Museum of Leonardo and I was amazed how one person can affect the lives of science through the centuries. Thank you Bulent for your interesting works.

    • Thank you, Serghei, for your note. The Museum of Science in Milan, especially the wing featuring replicas of Leonardo’s inventions, is very impressive. But, only 20-25% of his original notes have survived. We shall never know what else he had discovered… what else he was thinking. Incidentally, there is an interest story about the replicas. In the 1930s, Mussolini had hired an engineer, Roberto Guatelli, to make replicas from the existing drawings. Shortly before WWII started, the collection of Leonardo’s machines were sent to be displayed in Tokyo. During the war they were trapped in Tokyo, and destroyed in American bombing. But after the war, IBM hired Guatelli to re-create the inventions. In time, Guatelli set up a firm, and replicated several collections, that were allowed to tour. I imagine the collections in Milan, Florence, Amboise… were created locally, or purchased from Guatelli’s firm. Again, thanks for he comment.

  • John Maenhout

    Dear Bulent,
    After reading this particular reference work I have learned a lot. You’re a crack in this matter, many of the inventions you have cited are inventions I had never known before. That he created only 17 paintings has led to much debate, but you assert this, so this case can be considered solved. That he has designed weapons was entirely unknown to me. He was a man that really could handle different issues, his style has left me awe struck. Left handed guitarists are the best in their fields, perhaps Leonardo similarly was best in writing with his left hand, and better than others.

    • Thank you for the comment, John. There will still be debate about how many paintings he personally finished. Only half-a-dozen are without doubt entirely by his hand. Other paintings he probably started, and let his assistants finish. I did not know about left-handed guitarists being the most skillful, but I am not surprised. Among left-handers in history are Alexander the Great, Julius Caesar, Isaac Newton, Beethoven, and I believe four of the last five Presidents of the United States. They seem to think “outside the box.” I am personally jealous of left-handed Italians.


    Dear Mr. Atalay,
    What a remarkable accomplishment for your hard work
    and diligence . You enriched my knowledge,Thank you
    very much .

    • Thank you for the gracious note, Mrs. Donenfeld, for the note from Down Under. Leonardo would have been fascinated that technology has brought us to the point where we can communicate virtually instantaneously, and discuss his ideas from five hundred years ago.

  • Didi Massoud

    My dear friend, it is a brilliant study of this illustrious man
    Very unteresting details
    I enjoyed your work
    Warm regards

    • Hello Didi, thank you for the note from the Loire Valley, France, where Leonardo spent the last three years of his life.

  • Lina D. Nelson

    Dear Bulent,
    I always enjoy reading your blogs. I find them fascinating and extremely informative. I look forward to reading more about Leonardo.

  • acne treatment

    I discovered this info earlier these days whilst within the workplace. Very helpful. Sent the link to myself and will probably bookmark it once I make it home.

  • italo nascimento

    I just noticed that the word ‘augmented’ is written wrong (as augmneted). It was hard to find out what it was. Nice text

About the Blog

Researchers, conservationists, and others share stories, insights and ideas about Our Changing Planet, Wildlife & Wild Spaces, and The Human Journey. More than 50,000 comments have been added to 10,000 posts. Explore the list alongside to dive deeper into some of the most popular categories of the National Geographic Society’s conversation platform Voices.

Opinions are those of the blogger and/or the blogger’s organization, and not necessarily those of the National Geographic Society. Posters of blogs and comments are required to observe National Geographic’s community rules and other terms of service.

Voices director: David Braun (

Social Media