The Greek scholar of natural history Eratosthenes of Cyrene (ca. 275-ca.195 BC) was proficient in many fields, but his most outstanding work was probably in mathematics and geography.

The Lexicon of Suidas (ca. 10th century A.D.) records the birth of Eratosthenes as the 126th Olympiad (276-272 B.C.), but since he was a pupil of Zeno (died 262-261) and since a number of authorities describe him as an old man of 80, it is more probable that he was born about 275 B.C. He studied grammar in Alexandria but was educated in philosophy in Athens, where he was influenced by the philosophers Arcesilaus and Ariston. About the age of 40 Eratosthenes was recalled to Alexandria by Ptolemy III to take charge eventually of the famous library of the Alexandrian Museum, succeeding Apollonius of Rhodes.

Eratosthenes wrote works of literary criticism (On Ancient Comedy), philosophy, history (establishing chronology as a...