BornBefore 285 BCE
Diedc. 222 BCE
Alexandria, Egypt
NationalityAlexandrian Greek
Scientific career
Ctesibius' water clock, as visualized by the 17th-century French architect Claude Perrault

Ctesibius or Ktesibios or Tesibius (Greek: Κτησίβιος; fl. 285–222 BCE) was a Greek inventor and mathematician in Alexandria, Ptolemaic Egypt.[1] Very little is known of Ctesibius' life, but his inventions were well known in his lifetime.[2] He was likely the first head of the Museum of Alexandria. He wrote the first treatises on the science of compressed air and its uses in pumps (and even in a kind of cannon). This, in combination with his work On pneumatics on the elasticity of air, earned him the title of "father of pneumatics." None of his written work has survived, including his Memorabilia, a compilation of his research that was cited by Athenaeus. Ctesibius' most commonly known invention today is a pipe organ (hydraulis), a predecessor of the modern church organ.


Ctesibius was the son of a barber, born c. 300 BCE, probably – but not certainly – in Alexandria.[a][2][5] He began his career as a barber, following his father.[2]

During this first career, he invented a counterweight-adjustable mirror. Another of his inventions was the hydraulis, a water organ that is considered the precursor of the modern pipe organ and the first keyboard instrument.[2] He and his wife Thais were reputed to be highly-skilled players of the instrument.[6][7] He improved the water clock or clepsydra ('water thief'), which for more than 1,800 years was the most accurate clock ever constructed, until the Dutch physicist Christiaan Huygens' invention of the pendulum clock in 1656. Ctesibius described one of the first force pumps for producing a jet of water, or for lifting water from wells. Examples have been found at various Roman sites, such as at Silchester in Britain. The principle of the siphon has also been attributed to him.

Hydraulic clock of Ctesibius, reconstruction at the Technological Museum of Thessaloniki


According to Diogenes Laërtius, Ctesibius was miserably poor. Laërtius details this by recounting the following concerning the philosopher Arcesilaus:

When he had gone to visit Ctesibius who was ill, seeing him in great distress from want, he secretly slipped his purse under his pillow; and when Ctesibius found it, "This," said he, "is the amusement of Arcesilaus."

Ctesibius's work is chronicled by Vitruvius, Athenaeus, Pliny the Elder, and Philo of Byzantium who repeatedly mention him, adding that the first mechanicians such as Ctesibius had the advantage of being under kings who loved fame and supported the arts. Proclus (the commentator on Euclid) and Hero of Alexandria (the last of the engineers of antiquity) also mention him.



  1. ^ There is no direct evidence for the place of birth of Ctesibius. He is given Alexandrinus, lit.'the Alexandrian', as "an ethnic" or "a deme" (the element in traditional Greek onomastic formulae ascribing geographic or ethnic origin),[3] in early mentions and reference to his work, including by Vitruvius (1st century BCE) in De Architectura.[4]


  1. ^ Encyclopædia Britannica: Ctesibius. "Greek physicist and inventor, the first great figure of the ancient engineering tradition of Alexandria, Egypt."
  2. ^ a b c d Hoffmann, James J. (2001). "Ctesibius of Alexandria". In Neil Schlager (ed.). Science and Its Times: Understanding the Social Significance of Scientific Discovery. Vol. 1 2000 BC to AD 699. Associate editor: Josh Lauer. Gale Group. pp. 400–401. Ctesibius (also spelled Ktesibios) was a Greek physicist and inventor who was probably born in Alexandria sometime around 300 B.C. He was the first of many Greeks to become part of the great ancient engineering tradition in Alexandria.
  3. ^ Rizakis, Athanasios (April 2019). "New Identities in the Greco-Roman East: Cultural and Legal Implications of the Use of Roman Names". In Robert Parker (ed.). Changing Names: Tradition and Innovation in Ancient Greek Onomastics. British Academy. pp. 237–257. doi:10.5871/bacad/9780197266540.003.0011. ISBN 978-0-19-188424-5.
  4. ^ Vitruvius. De Architectura. Book IX, Chapter 8.2.
  5. ^ Pollard, Justin; Reid, Howard (2007). "The Clockwork City". The Rise and Fall of Alexandria: Birthplace of the Modern World. Penguin Books. p. 130. ISBN 978-0143112518.
  6. ^ Athenaeus Deipnosophistae 4.174e
  7. ^ Leon, Vicki (1995). Uppity Women of Ancient Times. Conari Press. p. 82. ISBN 9781573240109.
  8. ^ "Ctesibius". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.

Further reading