III · The Great Librarians · c. 245 BCE
Eratosthenes summoned; he measures the Earth
Known · AttestedKnown · AttestedHis summons and his measurementKnown · ProbableThat he came as tutor to the future Ptolemy IVLegend · Told storyThe well at Syene of popular retellings
Ptolemy III calls Eratosthenes of Cyrene from Athens to Alexandria to head the Library; the papyrus list puts him after Apollonius, the Suda before. It is usually inferred that he also tutored the king's son. He measures the Earth's circumference from the angle of the noon sun, and founds scientific chronology; Archimedes sends him the Method.
What the evidence supports: Cleomedes's account of the method has no well at Syene; how close he came depends on the length of his stade, which is disputed.
Who and what
- Places
- The royal Library
In the show
The show has not yet spoken of this moment.
Sources (6)
- Suda ε 2898
- Suda α 3419
- P.Oxy. X 1241 (ed. B. P. Grenfell and A. S. Hunt, The Oxyrhynchus Papyri X, London 1914) col. ii (opens in a new tab)
- Cleomedes, Caelestia 1.7
- Archimedes, Method preface
- D. W. Roller, Eratosthenes' Geography (Princeton: Princeton University Press, 2010)