Codex Leicester

Codex Leicester
Codex Hammer
Bill Gates estate (since 11 November 1994)
TypeCodex
Datec. 1506 – c. 1508 and c. 1510 – c. 1512
Place of originFlorence, Italy
LanguageItalian
AuthorLeonardo da Vinci
MaterialRag paper
Size
  • 18 sheets, 72 folio pages
  • ~400 mm (16 in) by ~300 mm (12 in)
ConditionUnbound, separately mounted
ScriptHandwritten mirror script
ContentsRenaissance science
AdditionsWatermarks
Previously kept

The Codex Leicester (also briefly known as the Codex Hammer) is a collection of scientific writings by Leonardo da Vinci. The codex is named after Thomas Coke, Earl of Leicester, who purchased it in 1719. The codex provides an insight into the mind of the Renaissance 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 at Christie's auction house on 11 November 1994 in New York for US$30,802,500 (equivalent to $67 million in 2025), it was the most expensive manuscript ever sold.