Eratosthenes was born in 276 BCE in Cyrene. A Greek scholar from Cyrene who became chief librarian of the Library of Alexandria, Eratosthenes was a pioneer of geography, a term he is credited with coining. He is best known for estimating the circumference of the Earth by comparing the angle of the sun's shadow at Alexandria with that at Syene during the summer solstice, getting a result remarkably close to the true figure. He also produced a map of the known world, devised the sieve of Eratosthenes for finding prime numbers, and worked on chronology and literary criticism. His nickname Beta suggested he was second best in many fields.
Before and after
- from 281 BCE to 62 CEKingdom of Pontus
- from 280 BCE to 146 BCEFounding of Achaean League
- from 280 BCE to 275 BCEPyrrhic War
- from 279 BCE to 1480Construction of Lighthouse of Alexandria
- 276 BCEBirth of Eratosthenes
- from 274 BCE to 168 BCESyrian Wars
- c. 270s BCEAristarchus of Samos proposes that the Earth orbits the Sun
- from 267 BCE to 261 BCEChremonidean War
- from 264 BCE to 146 BCEPunic Wars
More in Science & technology
- 460 BCEBirth of Hippocrates
- 287 BCEBirth of Archimedes
- 212 BCEDeath of Archimedes
- c. 131 BCEHipparchus discovers the precession of the equinoxes
- 1 January 45 BCEThe Julian calendar takes effect
- 132 CEZhang Heng builds the first seismoscope
The era
This moment belongs to the Ancient civilizations (3,200 BCE to 500 CE), writing, cities and empires. You can also browse everything in the 3rd century BCE.