The Codex Leicester (also briefly known as the Codex Hammer) is a collection of scientific writings by

Leonardo da Vinci Leonardo di ser Piero da Vinci (15 April 1452 - 2 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially rested o ...

. The

codex The codex (: codices ) was the historical ancestor format of the modern book. Technically, the vast majority of modern books use the codex format of a stack of pages bound at one edge, along the side of the text. But the term ''codex'' is now r ...

is named after Thomas Coke, Earl of Leicester, who purchased it in 1719. The codex provides an insight into the mind of the

Renaissance The Renaissance ( , ) is a Periodization, period of history and a European cultural movement covering the 15th and 16th centuries. It marked the transition from the Middle Ages to modernity and was characterized by an effort to revive and sur ...

artist, scientist and thinker, as well as an exceptional illustration of the link between art and science and the creativity of the scientific process. When the manuscript was last sold to

Bill Gates William Henry Gates III (born October 28, 1955) is an American businessman and philanthropist. A pioneer of the microcomputer revolution of the 1970s and 1980s, he co-founded the software company Microsoft in 1975 with his childhood friend ...

Christie's Christie's is a British auction house founded in 1766 by James Christie (auctioneer), James Christie. Its main premises are on King Street, St James's in London, and it has additional salerooms in New York, Paris, Hong Kong, Milan, Geneva, Shan ...

auction house on 11 November 1994 in New York for (equivalent to $ million in ), it was the most expensive manuscript ever sold.

Manuscript

The leather-bound notebook comprises 36 sheets, 29 × 22 cm. The manuscript is not a single linear script but a mixture of Leonardo's observations and theories on

astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

and the properties of water, rocks, fossils, air, and celestial light. The topics addressed include: * An explanation of why

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s of sea creatures can be found on mountains. Hundreds of years before

plate tectonics Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

became accepted scientific theory, Leonardo believed that mountains had previously formed sea beds, which were gradually lifted until they formed mountains. * The movement of water. This is the main topic of the Codex Leicester. Among other things, Leonardo wrote about the flow of water in rivers and how it is affected by different obstacles put in its way. He made recommendations about bridge construction and

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

from his observations. * The luminosity of the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

. Leonardo speculated that the Moon's surface is covered by water, reflecting the Sun's light. In this model, waves on the water's surface cause the light to be reflected in many directions, explaining why the Moon is not as bright as the Sun. Leonardo explained that the pale glow on the dark portion of the crescent Moon is caused by sunlight reflected from the Earth. Thus, he described the phenomenon of

planetshine Planetshine is the dim illumination, by sunlight reflected from a planet, of all or part of the otherwise dark side of any natural satellite, moon orbiting the body. Planetlight is the diffuse reflection of sunlight from a planet, whose albedo ...

one hundred years before the German astronomer

Johannes Kepler Johannes Kepler (27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, Natural philosophy, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best know ...

proved it. The codex consists of 18 sheets of paper, each folded in half and written on both sides, forming the complete 72-page document. At one time the sheets were bound together, but they are now displayed separately. It was handwritten in

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, a Romance ethnic group related to or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance languag ...

by Leonardo, using his characteristic

mirror writing Mirror writing is formed by writing in the direction that is the reverse of the natural way for a given language, such that the result is the mirror image of normal writing: it appears normal when reflected in a mirror. It is sometimes used as ...

, and supported by copious drawings and diagrams.

History

Historical owners

Guglielmo della Porta Guglielmo della Porta (c. 1500–1577) was an Italian architect and sculptor of the late Renaissance or Mannerism, Mannerist period. He was born to a prominent North Italian family of masons, sculptors and architects. His father Giovanni Battista ...

Michelangelo Michelangelo di Lodovico Buonarroti Simoni (6March 147518February 1564), known mononymously as Michelangelo, was an Italian sculptor, painter, architect, and poet of the High Renaissance. Born in the Republic of Florence, his work was inspir ...

's student (?) * Giuseppe Ghezzi (until 1719) * Thomas Coke, 1st Earl of Leicester (1719–1759) * Leicester estate (1759–1980)

Codex Hammer

The codex was purchased at auction from the Leicester estate in 1980 by the wealthy industrialist and art collector

Armand Hammer Armand Hammer (May 21, 1898 – December 10, 1990) was an American businessman and philanthropist. The son of a Russian Empire-born communist activist, Hammer trained as a physician before beginning his career in trade with the newly estab ...

, for $5.1 million (equivalent to $ million in ); he later renamed the notebook the Codex Hammer. Hammer commissioned Leonardo da Vinci scholar Carlo Pedretti to compile the loose pages of the codex back into its original form. Over the next seven years, Pedretti translated each page to English, completing the project in 1987.

Bill Gates

The codex was sold to

auction house on 11 November 1994 in New York for . Until 2021, the codex remained the most expensive book ever sold. After Gates acquired the codex, he had its pages scanned into digital image files, some of which were later distributed as

screensaver A screensaver (or screen saver) is a computer program that blanks the display screen or fills it with moving images or patterns when the computer has been idle for a designated time. The original purpose of screensavers was to prevent phosphor s ...

and

wallpaper Wallpaper is used in interior decoration to cover the interior walls of domestic and public buildings. It is usually sold in rolls and is applied onto a wall using wallpaper paste. Wallpapers can come plain as "lining paper" to help cover uneve ...

files on a

CD-ROM A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains computer data storage, data computers can read, but not write or erase. Some CDs, called enhanced CDs, hold b ...

as part of a Microsoft Plus! for Windows 95 desktop theme, which would later be included with

Windows 98 Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the second operating system in the 9x line, as the successor to Windows 95. It was Software ...

and

Windows ME Windows Me (Millennium Edition) is an operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the successor to Windows 98, and was released to manufacturing on June 19, 2000, and t ...

. A comprehensive CD-ROM version (titled ''

'') was released by Corbis in 1997. The Codex Leicester has been unbound and each page individually mounted between glass panes. It is on public display once a year in a different city worldwide. In 2000, it was displayed at Sydney's Powerhouse Museum. In 2004, it was exhibited in the Château de Chambord, and 2005 in

Tokyo Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...

. One page was exhibited at the Seattle Museum of Flight's 2006 exhibit ''Leonardo da Vinci: Man, Inventor, Genius''. From June to August 2007, the codex was the centerpiece of a two-month exhibition hosted by the

Chester Beatty Library The Chester Beatty Library, now known as the Chester Beatty, is a museum and library in Dublin. It was established in Ireland in 1953, to house the collections of mining magnate, Sir Alfred Chester Beatty. The present museum, on the grounds of ...

Dublin Dublin is the capital and largest city of Republic of Ireland, Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, and is bordered on the south by the Dublin Mountains, pa ...

. The codex was on view at the

Phoenix Art Museum The Phoenix Art Museum is the largest art museum, museum for visual art in the southwest United States. Located in Phoenix, Arizona, the museum is . It displays international exhibitions alongside its comprehensive collection of more than 18,0 ...

Phoenix, Arizona Phoenix ( ) is the List of capitals in the United States, capital and List of cities and towns in Arizona#List of cities and towns, most populous city of the U.S. state of Arizona. With over 1.6 million residents at the 2020 census, it is the ...

, from 24 January 2015 to 12 April 2015 for the exhibition ''Leonardo Da Vinci's Codex Leicester and the Power of Observation''. Its presentation at the Phoenix Art Museum was the first time a work by Leonardo was displayed in Arizona. The codex was then on view at the Minneapolis Institute of Arts in an exhibition ''Leonardo Da Vinci, the Codex Leicester, and the Creative Mind'' that opened 21 June 2015, where it remained on display until 30 August 2015. As part of the same tour, the Codex Leicester was also on display at the North Carolina Museum of Art in Raleigh, North Carolina from 31 October 2015 to 17 January 2016. For the 500th anniversary of Leonardo's death, the Codex Leicester was on display from 29 October 2018 to 20 January 2019 in

Florence Florence ( ; ) is the capital city of the Italy, Italian region of Tuscany. It is also the most populated city in Tuscany, with 362,353 inhabitants, and 989,460 in Metropolitan City of Florence, its metropolitan province as of 2025. Florence ...

at the Aula Magliabechiana of the

Uffizi The Uffizi Gallery ( ; , ) is a prominent art museum adjacent to the Piazza della Signoria in the Historic Centre of Florence in the region of Tuscany, Italy. One of the most important Italian museums and the most visited, it is also one of th ...

References

External links

News report of Japan opening, September 2005

Leonardo da Vinci: The Codex Leicester

Chester Beatty Library, Dublin, Ireland

The sale of the Codex Hammer, 11 November 1994

Water as Microscope of Nature: Leonardo da Vinci's Codex Leicester, exhibition in Florence, Uffizi Galleries